Robinson, Colin
Nelson, 1971
Buku Teks
Bassie, V. Lewis
McGraw-Hill Book Company, Inc , 1958
Buku Teks
edited by Elizabeth Marting
American Management Association , 1957
Buku Teks
Levenbach, Hans
Lifetime Learning Publications, 1981
Buku Teks
Hanke, John E.
Pearson - Prentice Hall, 2009
Buku Teks