Reference etiquatte:a guide to excruciatingly correct bahavior
 Artikel Jurnal
Shurter, Robert L.
Handy grammar reference: a guide to better English / Robert L. Shurter
McGraw-Hill, 1959
 Buku Teks SO
Cameron hydraulic data : a handy reference on the subject of hydraulics
Ingersoll-Rand Company, Cameron Pump Division, 1939
 Buku Teks
Evans, Graham
The dictionary of world politics : a reference guide to concepts, ideas, and institutions
Harvester Wheatsheaf, 1990
 Buku Referensi
Wichman, Karl
Handy dictionary of the German and English languages with rules as to pronuciation
Philadelphia, David McKay Company, 1944
 Buku Referensi