Malthus, T.R.
N.Y. Kelley & Millman , 1954
Buku Teks
Huszar, George B. de (George Bernard), 1919-1968, author
Littlefield, Adams, 1959
Buku Teks
Pounds, Norman J. G., author
McGraw-Hill, 1972
Buku Teks
edited by Heinz Eulau and James G. March
Prentice-Hall, 1969
Buku Teks
Cambridge University Press, 2003
Buku Teks