Carr-Saunders, A.M.
Frank Cass, 1964
Buku Teks
Borrie, W.B.
Weidenfeld and Nicolson, 1970
Buku Teks
National Academy of Sciences-National Research Council , 1963
Buku Teks
Otero, George G.
University of Denver, 1981
Buku Teks
Russell, Sir E. John
George Allen and Unwin, 1961
Buku Teks