by Horace D. Crockford [and others]
John Wiley & Sons, 1975
Buku Teks
Anderson, Franz E., author
Burgess Publishing, 1979
Buku Teks
Gerking, Shelby D., author
Burgess, 1970
Buku Teks
edited by Philip C. Laris, Jack G. Reynolds
Burgess, 1970
Buku Teks
Patterson, C.O. Pat, author
Burgess Publishing , 1973
Buku Teks