Houghton Mifflin , 1993
Buku Referensi
edited by Jerri Killian; Niklas Eklund
CRC Press, 2008
Buku Teks
Glover, John D.
Harvard University, Division of Research, Graduate School of Business Administration, 1960
Buku Teks
Rand, 1979
Buku Teks
Doris, Lillian
Prentice-Hall, 1960
Buku Teks