While other word categories in Ilocano are not as diverse in forms, verbs are morphologically complex inflecting chiefly for aspect. Ilocano verbs can also be cast in any one of five foci or triggers. In turn, these foci can inflect for different grammatical moods.
Reduplication
An important aspect of Ilokano verbal morphology is reduplication. Reduplication in verbal paradigms consists of repeating the first /(C1)V(C2).../ sequence of phonemes of the root as required by the form resulting in a bimoraic or heavy syllable. Or, the first /(C)V/ is repeated as is the case for indicating plural actors.
The glottal stop as the second consonant of the sequence (C2) is lost. Two strategies can be applied to maintain the weight of the reduplicated syllable. Either the vowel (V) is lengthened (compensatory lengthening) or the first consonant (C1) is doubled (geminated).
Neutral - The neutral form is not marked for aspect (perfective or imperfective) or initiation (initiated or non-initiated) nor tense (past or non-past). It serves as the form for both the infinitive and the imperative.
Perfective - A completed action or accomplished state.
Imperfective - A non-punctual, repeated or habitual action or continued state.
Past Imperfective - A non-punctual, repeated or habitual action occurring in the past or a state that continued in the past.
In the typical verbal paradigm, Neutral and Perfective forms are not reduplicated, whereas the Imperfective and the Past Imperfective are reduplicated. The Imperfective and the Past Imperfective are marked for initiation.
Conjugation Pattern
Non-Initiated
Initiated
Simple
Neutral
Perfective
Reduplicated
Imperfective
Past Imperfective
In a typical paradigm the chart would appear as the following:
Conjugation Pattern
Non-Initiated
Initiated
Simple
[AFFIX]
[AFFIX+N]
Reduplicated
[AFFIX]+[CVC]
[AFFIX+N]+[CVC]
[AFFIX] is the verbal affix. [AFFIX+N] is the verbal affix modified for initiation. In many of the paradigms, the mark of initiation is N, for example, nag-, na-, and -in-. [CVC] is the reduplicated syllable of the root.
Future
The future is not encoded with a particular verbal form. It is shown by affixing the enclitic -(n)to to the neutral form of the verb. The enclitic is not very cohesive. When it attaches, the personal pronoun enclitics intervene. If the preceding morpheme ends in a vowel, the form is -nto, otherwise, -to.
Examples:
Kitaento see (something)kita[Root: see] + en[Patient Focus]Kitaentoto about to see (something)kita[Root: see] + en[Patient Focus] + to[Fut. Part.]KitaennantoHe/she will see (something)kita[Root: see] + en[Patient Focus] + na[3rd Person Singular Ergative] + nto[Fut. Part.]KitaendaktoThey will see mekita[Root: see] + en[Patient Focus] + dak[3rd Per. Plu. Erg./1st Per. Sing.] + to[Fut. Part.]
Focus
Ilocano, like other Philippine languages, has an Austronesian morphosyntactic alignment. The verb is capable of tracking (focusing) on particular noun phrases within the sentence. Ilokano verbs are capable of focusing on noun phrases with the following thematic roles: Agent, Patient, Commitative, Directional, Benefactive, Thematic and Instrumental.
The Agent focus requires only one noun phrase. According to Galvino (2000), the affixes in the Agent focus are Intransitive, because the verb form does not require another noun phrase to complete its meaning. The noun phrase is the agent or the experiencer of the action.
The remaining foci, Patient, Commitative, Directional,
Benefactive, Thematic and Instrumental require the presence of two theta roles: the agent noun phrase and the focused noun phrase. Galvino (2000) terms these as Transitive.
Potentially, all roots can be cast into all of the foci. Due to the semantics of the root, however, not many do in practice. Roots can differ in meaning when cast into different foci. The difference can be a slight nuance to almost opposite in meaning. For example, if the root dalusclean is cast in the Patient focus, the resulting meaning is to clean (something). But, if cast in the Directional focus, the resulting meaning is to clean (something) off, the focused noun phrase becomes the area affected instead of the object affected.
Foci and Corresponding Affixes
Focus
Conjugation
Example
Gloss
Agent
<um>
gumatang
to buy
ag-
aggatang
to buy (again and again), to shop
mang-
manggatang
to buy
ma-
maturog
to sleep
Patient
-en
dalusen
to clean (something)
Commitative
ka-
kasao
to talk with (someone)
Locative
-an
dalusan
to clean (something) off
Thematic
i-
iruar
to put (something) outside
Benefactive
i> <an
igatangan
to buy for someone
Instrumental
pag-
pagdalus
to use something to clean
Agent Focus
Verbs cast in this focus throw emphasis on the noun phrase with the agent or experiencer role in the sentence. Impersonal verbs and verbs describing natural phenomenon occur with this focus, for example Agar-arbisIt is drizzling.[2]
Noun phrases in the agent role are introduced by the core forms of the articles, ti for common nouns and ni for personal nouns. The enclitic absolutive (-ak series) of personal pronouns replace these noun phrases. If the verb can take a direct object, it is marked by the oblique forms of the articles, deictives and pronouns, for example, Nangan iti sabaHe ate a banana. Notice how the direct object is indefinite.
Patient role noun phrases (direct objects) of verbs are introduced by the oblique forms. In addition, Patients of verbs cast in the agent focus are indefinite.[3]
There are four affixes in this focus category: ag-, -um-, mang- and ma-. Roots will prefer to take only one or some of the prefixes. In some cases the meaning changes from one affix to another, for example, ngisit, black. If ag- is affixed, agngisit, the meaning is that of there is a likelihood of becoming black or to darken, for example Nagngisitka, You darkened.[4] However, with -um-, ngumisit, the meaning becomes more of a possibility or conjecture, Ngumisngisitkansa iti tengnat' aldaw, You might get darker at midday.
Ag-
The verbal prefix ag- is very productive and can verbalize a large number of roots. If a new word were to enter the language, most likely this is the prefix used to verbalize it, for example, the fictitious baz: agbazto "baz".
If the root takes either ag- or -um-, the additional meaning of ag- are some of the following:
Repetition of the action
Long duration of the action
With some roots, the attainment of the root, for example, dakkel, big, agdakkelto be big, doktordoctor, agdoktorto be a doctor.
The actor is in full control (internally motivated)
The certainty of the action because it is habitually occurring or frequently occurring.
Denotes the action taken on with the root, palsiitblowgun, agpalsiitto shoot with the blowgun, use the blowgun. (Compare with -um- below.)
Ag-
Aspect
Form
Example
Gloss
Neutral
ag-
agtaray
to run
Continuous Progressive
agCVC-
agtartaray
is/was running
Perfective
nag-
nagtaray
ran
has/have run
Continuous Complete
nagCVC-
nagtartaray
was/were running
used to run
would run
<um>
The verbal prefix <um>, is inserted, or infixed, to the first syllable of the root.
Some of the meanings imparted using this infix are:
A single action or an action that is not as long in duration as what is denoted by ag-.
With certain roots, using <um> denotes the act of "becoming" the root, for example, lakayold man, lumakayto grow older, to become older (said of males), to become an old man.
The actor is externally or circumstantially motivated.
The possibility of the action. (Compare with ag- above.)
<um>
Aspect
Form
Example
Gloss
Neutral
<um>
gumatang
to buy
Continuous Progressive
C<um>VC~
gumatgatang
buys
is/are buying
Perfective
<imm>
gimmatang
bought
has/have bought
Continuous Complete
C<imm>VC~
gimmatgatang
is/was buying
used to buy
would buy
Ag- Versus <um>
The affixes ag- and <um> are very similar. Many verbs take either and have little difference in meaning. Other verbs are drastically differentiated.[5] Below is a chart contrasting the two.
Ag- Versus <um>
Feature
Ag-
<um>
Repetition
Multiple
At least once, Very few
Duration
Long
Short
Motivation
Internal
External, Circumstantial
Control
Controlled
Not Controlled
Probability
Likely
Conjectured
State
Attained
In progress, Becoming
Examples
Feature
Ag-
<um>
Root
Repetition
aginom, to drink often, drink alcohol
uminom, to drink (water, juice, etc.)
inom, drink
Duration
agtakder, to stand
tumakder, to stand up
takder, upright
Motivation
agkabaw, to be forgetful, go senile
kumabaw, to become senile
kabaw, senile
Control
agsao, to speak
sumao, to speak up, to be heard
sao, word, speech
Probability
agkagat, to bite (likely)
kumagat, to bite (seemingly)
kagat, (a) bite
State
agbaknang, to be rich
bumaknang, to become rich
baknang, riches
Mang-
The mang- prefix is used to denote the following:
Collection or gathering
Purchase
Movement
Occupation and identification
The final nasal, /ŋ/, of the prefix commonly becomes the homorganic nasal of the first consonant of the root which disappears or remains.
This affix is used when it is necessary to make a normally transitive verb, a verb that commonly occurs with -en, -an or i-, intransitive for syntactic reasons. These verbs will take mang- in such instances.
Nasal assimilation
Consonant
Nasal
Form
Example Root
Example Form
/p/,/b/,/m/
/m/
mam-
baka, cow
mamaka, to buy cows
/t/,/d/,/s/,/n/
/n/
man-
talon, field
manalon, to work in the field, farmer
/k/, /ɡ/, /ŋ/
/ŋ/
mang-
kayo, wood, tree
mangayo, to collect wood, wood collector
All others
/ŋ/
mang-
ubas, grapes
mangubas, to gather grapes
Mang-
Aspect
Form
Example
Gloss
Neutral
mang-
mangrugi
to start
Continuous Progressive
mangCVC-
mangrugrugi
starts
is/are starting
Perfective
nang-
nangrugi
started
has/had started
Continuous Complete
nangCVC-
nangrugrugi
was/were starting
used to start
would start
Ma-
There are few verbs with active meaning that use this prefix. Some of these are maturog (<turog), to sleep, mapan (<pan), to go, magna (<pagnairregular formation), to walk. Because of the semantics of these roots, they cannot take a direct object.
In the continuous progressive form, the prefix participates in reduplication taking the first consonant as its final, unlike the other verbal prefixes.
Lastly, ma- is similar in form to the ma- potentive. They differ in terms of the series of pronouns they are able to take: ma- (agent) take -ak pronouns; ma- (potentives) take -ko.
Ma-
Aspect
Form
Example
Gloss
Neutral
ma-
maturog
to sleep
Continuous Progressive
maCma-
matmaturog
sleeps
is/are sleeping
Perfective
na-
naturog
slept
has/have slept
Continuous Complete
naCna-
natnaturog
was/were sleeping
used to sleep
would sleep
Patient Focus: -En
Verbs cast in this focus throw emphasis on the patient of the verb, in other words, the direct object. Because of this, the misnomer "passive voice" has been applied to verbs in the patient focus.
Agents (or actors) for verbs cast in the true passive voice can be omitted. The English sentence The car was repaired yesterday is grammatical without the agent of the verb.[6] This cannot be said of verbs in the patient focus. Patient focus verbs require both the agent and the object argument for grammaticality. The sentence Tinarimaan ti mekaniko ti kotse is more grammatical than *Tinarimaan ti kotse which lacks an agent.
Patients of verbs cast into this focus are definite.[3] Both actor and patient are both marked by the core form of the article and deictives. For the pronouns, the ergative forms are used, in other words, the -ko series of pronouns. Since the core forms are used for both actor and patient, they are differentiated only by syntax: the actor follows after the verb as close as possible with the patient thereafter. If pronouns are used for both the actor and patient, a special set of pronouns are used. Consult the table of pronoun sequences for details.
What can be considered the patient of an English verb, may be cast in a different theta role in Ilocano. Take for example, the English phrase The student saved the file. In this phrase, the file is the noun phrase in the patient role (the direct object). In Ilocano, however, the same noun phrase would be cast in the thematic role and the verb in the thematic focus, instead, Indulin ti estudiante ti file because of the semantics of the verb. In the Ilocano mind, the file is being transferred to a safe place.
Use of this affix imparts the following meanings:
Consumption of the object, e.g. alimon "swallow", alimunen "to swallow (something)"
Permanent change of state, e.g. patay "death", patayen "to kill"
Mental processing of the object, e.g. panunot "thought", panunuten "to think (about something), ponder (something)"
Verbs in the comitative focus denote that the verb action is shared between parties. The focused noun phrase is with whom the agent is partaking the action. Similar to the Instrumental focus below, these behave more like nouns.
Ka-
Aspect
Form
Example
Gloss
Neutral
ka-
katungtung
to converse with someone
Continuous Progressive
kaCVC-
katungtungtung
converses with someone
is/are conversingwith someone
Perfective
kina-
kinatungtung
conversed with someone
has/have conversed with someone
Continuous Complete
kinaCVC-
kinatungtungtung
was/were conversing with someone
Directional Focus: -An
The focused noun phrases of directional verbs are treated as places or destinations. When a person is the focus, a notion of direction (either to or from) or an affected party is implied, for example, suratanto write to someone, takawanto rob from someone (compare with tawakento steal something). In addition, the focused noun phrase is treated as an area that is affected by the verb.
Verbs of cleaning, dalusan, to clean, labaan, to launder, sagadan, to sweep, are in this focus as the focused noun phrases are considered as an area affected. It is possible to use -en with these roots, but notice in the following sentences how the affix alters the focus and meaning: (with -an) Dinalusak ti sala. "I cleaned the living room." versus (with -en) Dinalusko ti rugit ti sala. "I cleaned the dirt in the living room."
Meanings:
Directionality, movement to or from
Place or destination
Area affected
Cleaning
-An
Aspect
Form
Example
Gloss
Neutral
-an
labaan
to launder something
Continuous Progressive
CVC~ -an
lablabaan
launders something
is/are laundering something
Perfective
<in> -an
linabaan
laundered something
has/have laundered something
Continuous Complete
C<in>VC~ -an
linablabaan
was/were laundering something
used to launder something
would launder something
Thematic Focus: i-
The focused noun phrases of thematic verbs are transferred or whose location or state is affected in some way by the semantics of the root. An analog of this idea of transference, verbs of saying are commonly use this affix. What is said becomes the focused element and is thought of as being transferred from one person to another.
Examples of roots that commonly take this form:
Transference, conveyance, e.g., dulinsafe place, idulin'to save, put away
Change of non-permanent state, e.g., lukatexposed, ilukatto open;rikepshut,irikepto close, to shut
Verbs that convey information or ideas - bagadeclaration, ibagato declare, say; kuna mention,ikunato mention
I-
Aspect
Form
Example
Gloss
Neutral
i-
ibaga
to say something
Continuous Progressive
iCVC-
ibagbaga
says something
is/are saying something
Perfective
in-
im-
ing-
imbaga
said something
has/have said something
Continuous Complete
inCVC-
imCVC-
ingCVC-
imbagbaga
was/were saying something
used to say something
would say something
Benefactive Focus: i><an
The focused noun phrases of the benefactive verbs are usually persons. The verb is performed on their behalf or for their benefit. In English, this would correspond to the indirect object or prepositional phrases introduced with to, for or because of.
As with non-actor verb forms, the core forms of the article and the deictives[check spelling], and the ergative, or -ko, forms of the personal pronouns mark the actor. The focus, in this case the benefactor, is marked with the core forms and the absolutive, or -ak forms of the personal pronouns. If there is a direct object, it is marked with the oblique forms, for example, Igatanganto ni nanang ni ading iti sapatosMother will buy shoes for (my) little sister.
Morphologically, the benefactive focused form is a combination of the prefix 'i-' and the suffix '-an'.
Meanings:
Benefit of the noun phrase in the absolutive
Representation
I><An
Aspect
Form
Example
Gloss
Neutral
i><an
igatangan
to buy for someone
Continuous Progressive
iCVC><an
igatgatangan
buys for someone
is/are buying for someone
Perfective
in><an
im><an
ing><an
inggatangan
bought for someone
has/have bought for someone
Continuous Complete
inCVC><an
imCVC><an
ingCVC><an
inggatgatangan
was/were buying for someone
would buy for someone
used to buy for someone
Instrumental Focus: Pag-
The basic sense of the instrumental focus is the use of something to accomplish the root's meaning; it is the tool or the means of achieving that end. That something is then cast in the absolutive case. For example, dalus, clean space, pagdalus, to use something to clean with.
Again, the actor is marked with the core forms or ergative, with pronouns (i.e., -ko), and the instrument, with core forms, and absolutive with pronouns, for example, Pagdalusan ni tatang ti drapoFather uses the rag to clean with.
Pag-, behaves more like a verbal noun than a verb and sometimes translates as the implement, the reason or the theme of the root instead. Because of this, formations with this affix are lexicalized, thus becoming a derivational affix in some instances.
Meanings:
Instrument
Means
Pag-
Aspect
Form
Example
Gloss
Neutral
pag-
pagdalus
to use something to clean
to be used to clean
Continuous Progressive
pagCVC-
pagdaldalus
uses something to clean
is/are using something to clean
is/are used to clean
Perfective
pinag-
pinagdalus
used something to clean
has/have used something to clean
was/were used to clean
Continuous Complete
pinagCVC-
pinagdaldalus
was/were using something to clean
used to use something for cleaning
would use something for cleaning
Imperative Mood
The imperative mood of the verb is used for giving commands or making requests.
The difference between the infinitive use and the imperative use is the accompaniment of a personal pronoun. These are the second person pronouns (singular or plural) and the first person plural inclusive.
Examples:
MangankaEat. (Second Person Singular)
Idissoyo ditoyPut it down here. (Second Person Plural)
Aginanata bassitLet's rest a while. (First Person Dual)
Imperative verbs do not inflect for aspect. Thus, they are not required to "agree" with the verb of the main clause when they occur in subordinate clauses.
Imbaga ni nanang a mangankaMother told you to eat.
Potentive Mood
The potentive mood of verbs denotes the following regarding the speaker's attitude regarding the event:
Unintentional - The actor had no intent in committing the action.
Possible - The actor had intent and was able.
Circumstantial - The actor was influence by the circumstances at the time.
Involuntary - The actor had no control over what happened.
Intransitive: Maka-, Makapag- and Makai-
The prefixes Maka-, Makapag- and Makai- corresponds to the following actor focus prefixes in the indicative mood.
Prefix
Indicative
Potentive
Root
ag-
aggatang, to buy
makagatang, makapaggatang to be able to buy
gatang, purchase
-um-
umuli, to ascend
makauli, to be able to ascend
uli, ascent
mang-
mangayo, to gather wood
makakayo, to be able to gather wood
kayo, wood, tree
ma-
maturog, to sleep
makaturog, to be able to sleep
turog, sleep
Maka-
Maka- is used with all of the other actors focus verbs except for some verbs that normally take ag-. It denotes the innateness of actor, or other factors such as health or knowledge, that affect one's ability to perform the action. It also denotes inattentiveness in the action if the verb can use either makapag- or maka-.
Aspect
Form
Example
Gloss
Neutral
maka-
makaturog
to be able to sleep
to be sleepy
Continuous Progressive
makaCVC-
makaturturog
is/are able to sleep
is/are sleepy
Perfective
naka-
nakaturog
was/were able to sleep,
had been able to sleep,
was/were sleepy
Continuous Complete
nakaCVC-
nakaturturog
was/were being able to sleep
was/were becoming sleepy
Makapag-
This prefix is applied to verbs that normally take ag- in the indicative. Similar to ag-, makapag- denotes internal motivation as a reason, so circumstance and context affect the ability to perform the action. Only nouns that denote humans or human-like animals are used with this prefix.
Aspect
Form
Example
Gloss
Neutral
makapag-
makapagdigos
to be able to bathe
Continuous Progressive
makapagCVC-
makapagdigdigos
is/are able to bathe
Perfective
nakapag-
nakapagdigos
was/were able to bathe
Continuous Complete
nakapagCVC-
nakapagdigdigos
was/were being able to bathe
Digos can also take maka-. But, with makapag-, one's ability to bathe will be determined by the availability of water, of the bathroom, of soap, of time, etc.
Makai-
The prefix makai- is used with detransitivized verbs that normally use i- as their transitive verb form, for example, ibellengto throw (something) out versus makaibellengcan throw out, to be able to throw out.
Aspect
Form
Example
Gloss
Neutral
maka-
makaibelleng
to be able to throw away
Continuous Progressive
makaiCVC-
makaibelbelleng
is/are able to throw away
Perfective
nakai-
nakaibelleng
was/were able to throw away
Continuous Complete
nakaiCVC-
nakaibelbelleng
was/were being able to throw away
Transitive: Ma-
The prefix ma- is used with the patient focused affixes. Unlike the actor focused counterpart, maka-, Ma- does not replace the prefix, but is prefixed to the unaltered form. The only exception is the patient focus, where the suffix -en is dropped.
Prefix
Example
Potentive Form
Root
Patient
kitaen
to see (something)
makita
to be able to see (something) to happen to see (something) to accidentally see (something)
to be able to talk with (someone) to happen to talk with (someone)
sao
speech
Directional
suratan
to write to (someone)
masuratan
to be able to write to (someone) to happen to write to (someone)
surat
writing, letter
Thematic
ibaga
to say(something)
maibaga
to be able to say (something) to happen to say (something)
baga
tell, say
Benefactive
igatangan
to buy for (someone)
maigatangan
to be able to buy for (someone) to happen to buy for (someone)
gatang
purchase
Instrumental
pagdalus
to used (something) to clean with
mapagdalus
to be able to used (something) to clean with to happen to used (something) to clean with
dalus
clean space
Examples:
Saanko nakasao ni maestra idi kalman.I was not able to talk to teacher yesterday. Nasuratam ida? Were you able to write to them? Maigatanganak ti libro? Can you buy me a book? Napagdalusko ti daan a kamisetam.I happened to use your old shirt for cleaning. (It was an accident. I promise!)
The inflectional forms for ma- potentives follow the same pattern detailed above in the Aspect section. In other words, the first syllable of the root reduplicates, not a part of the word before ma- is prefixed, for example, maibagbaga, is/are able to say (something), not *maib-ibaga.
In the initiated forms, the Continuous Progressive form is prefixed with na-, for example, ibagbagasays (something), maibagbagais/are able to say (something) and naibagbagawas/were being able to say (something), not *maimbagbaga or *naimbagbaga.
Example: ituding to specify (something)
Aspect
Form
Example
Gloss
Neutral
mai-
maituding
to be able to specify (something)
Continuous Progressive
maiCVC-
maitudtuding
is/are being able to specify (something)
Perfective
nai-
naituding
has/had been able to specify (something)
Continuous Complete
naiCVC-
naitudtuding
was/were being able to specify (something)
Causative: Pa-
Causatives are the verb forms where the agent causes or forces the patient to perform a given action or to become a given state. As a result, all causative verbs forms are transitive, requiring both agent and patient.
The common pattern of formation is: [FOCUS] + pa + [ROOT].
Agpa-, Mangpa-
Ipa-, Ipai-, Pa><an
Pagpa><an
Panagpa-
Ipa><an
Makapa-
Makipa-
Notes
^When the root begins with a vowel, underlyingly, the onset is the glottal stop which must be retained in reduplication. This is reflected in the orthography by using a hyphen, "-".
^On the other hand, non null-subject languages will require a subject with verbs of natural phenomenon, for example, Itis raining (English), Es regnet (German) and Ilpleut (French). The pronoun does not refer to anything, but it is required by the grammar that a subject exists in the subject frame.
^ abIn sentences where the agent role and the patient role noun phrase is the same, casting a verb in the agent or the patient focus changes the definiteness of the patient role noun phrase. When the verb is cast in the agent focus, the patient is indefinite, Gimmatangak ti asoI boughtadog (no specific dog is referenced). If cast in the patient focus, the patient role noun phrase become definite, Ginatangko ti asoI boughtthedog (referring to a particular dog).
^Incidentally, this is the intensive form of the adjective with the addition of -en. This is to say, that the state has been attained with some amazement of the speaker.
^Lobel, Jason (Dec 2004). "Old Bikol -um- vs. mag- and the Loss of a Morphological Paradigm". Oceanic Linguistics. 43 (2): 469–497. doi:10.1353/ol.2005.0007. JSTOR3623366.
^Note the use of the word agent and not subject since the subject of this sentence is the girl.
^The suffix drops off in the perfective, in contrast to -An, which remains.
^In writing there is no distinction between, maka- (actor focused potentive) and ma-+ka- (commitative focused pontentive). In speech, however, the ka- of the commitative focused pontentive (/ma.'ka/-) is stressed while maka-, the actor focused potentive it is not (/ma.ka/-).
References
Espiritu, Percy (December 1984). Let's Speak Ilokano. University of Hawai'i Press. ISBN0-8248-0822-3.
Rubino, Carl R. Galvez (February 2000). Ilocano Dictionary and Grammar: Ilocano-English, English-Ilocano (Pali Language Texts: Philippines). University of Hawai'i Press. ISBN0-8248-2088-6.
Rubino, Carl R. Galvez (May 1998). Ilocano: Ilocano-English/English-Ilocano Dictionary and Phrasebook. Hippocrene Books. ISBN0-7818-0642-9.