Moos, Malcolm
Random House, 1956
Buku Teks
edited by Andrew Rothstein and Clemens Dutt
Foreign Languages Pub. House, 1960
Buku Teks
[publisher not identified], 1957
Buku Teks
Hamm, Hary
Frederick A. Praeger, 1963
Buku Teks
D.C. U.S. Department of Labor , 1957
Buku Teks