Harman, Harry H., author
University of Chicago Press, 1968
Buku Teks
Harman, Harry H., author
The University of Chicago Press, 1976
Buku Teks
Whittaker, E.T.
Cambridge University Press, 1965
Buku Teks
Edwards, Allen L., author
Rinehart and Winston , 1958
Buku Teks
Stanford Univ. Press ., 1961
Buku Teks