Iowa State University Press , 1964
Buku Teks SO
International labour office , 1988
Buku Teks SO
Strong, Bryan
Wadsworth, 2008
Buku Teks
chapters by Edgar McInnis ... [et al.] ; edited by George W. Brown
University of California Press, 1953
Buku Teks SO
edited by George W. Brown
University of California Press, 1954
Buku Teks SO