Alixim Gorky ... [and others]
Progress, 1972.
Buku Teks
Hall, Oakley
Story Press, 1989
Buku Teks
Benson, Tedd, author
CT Taunton Press, 1999
Buku Teks
Eble, Kenneth E., author
Jossey-Bass, 1979
Buku Teks
Ehrenhaft, George
Prima Publishing, 1999
Buku Teks