King, William Richard, 1938-, author
Van Nostrand Reinhold, 1978
Buku Teks
King, William Richard, 1938-, author
McGraw-Hill, 1967
Buku Teks
Craffi, Stephen
Image Publishing, 2002
Buku Teks
Harper , 1962
Buku Teks
Covey, Stephen R., author
Pajusi Gunyeongsa, 2004
Buku Teks