Phelps, D.M.
Ill. Richard D. Irwin, Inc , 1947
Buku Teks
Smykey, Edward W., author
Macmillan, 1961
Buku Teks
Aaker, David A., author
John Wiley & Sons, 1984
Buku Teks
Agnew, Hugh E.
McGraw-Hill , 1951
Buku Teks
Agnew, Hugh E.
McGraw-Hill Book , 1950
Buku Teks