http://citation.dbpedia.org/hash2/56cc8f1f7f25aa2309decad2e9932f8b468a2978de680577946ae58f277f2ef4
1537
http://books.google.com/books?vid=ISBN0898201152
5
http://books.google.com/books?vid=ISBN0898201608
3
http://books.google.com/books?vid=ISBN9780898201604
3