Schubert, Glendon
Scott,Foresman and Company, 1974
Buku Teks
Cambridge University Press, 2019
eBooks
Choper, Jesse H.
The University of Chicago Press, 1980
Buku Teks
Koopmans, Tim
Cambridge University Press, 2003
Buku Teks
Jacob, Herbert, 1933-
Litle, Brown, 1978
Buku Teks