Chen, Kuan I.
Bookman Associates, 1960
Buku Teks
Carr-Saunders, A.M.
Frank Cass, 1964
Buku Teks
Thompson, Warren S.
McGraw-Hill, 1970
Buku Teks
Russell, Sir E. John
George Allen and Unwin, 1961
Buku Teks
Otero, George G.
University of Denver, 1981
Buku Teks