Perkins, John, author
Abdi Tandur, 2005
Buku Teks
Perkins, John, author
Berrett-Kochler , 2004
Buku Teks
Perkins, John
Berrett-Koehler Publishers, 2016
Buku Teks
Boulding, Kenneth E. (Kenneth Ewart), 1910-1993, author
Harper & Row, 1966
Buku Teks
Boulding, Kenneth E. (Kenneth Ewart), 1910-1993, author
Harper & Brothers, 1955
Buku Teks