Brown, Paul L.
Ronald Press Co , 1953
Buku Teks
Kelley, Pearce Clement, author
Prentice-Hall, 1957
Buku Teks
Bellenger, Danny N.
Richard D. Irwin, Inc., 1983
Buku Teks
Richert, G. Henry
McGraw-Hill Book Co., Inc. , 1962
Buku Teks
Cahill, Jane.
Fairchild Publications , 1960
Buku Teks