Linberg, Janice, author
J.B. Lippincott , 1983
Buku Teks
Barker, Clare Wright
McGraw-Hill Book Co. , 1956
Buku Teks
MacMillan Press , 1990
Buku Teks
Hamm, Harry
Doubleday & Company, Inc., 1966
Buku Teks
Hamm, Hary
Frederick A. Praeger, 1963
Buku Teks