^Pennsylvania. Dept. of General Services؛ Pennsylvania. Bureau of Publications؛ Pennsylvania. Dept. of Property and Supplies (1971). The Pennsylvania Manual. Department of General Services. ج. 100. ISSN:0275-8814. مؤرشف من الأصل في 2016-05-17. اطلع عليه بتاريخ 2014-11-18.