Monosson, Emily
Island Press, 2012
eBooks
Kelly, Mahlon G.
Houghton Miffiln, 1975
Buku Teks
edited by Bernard Stonehouse and Christopher M. Perrins
University Park Press, 1979
Buku Teks
Geist, Valerius
Springer-Verlag, 1978
Buku Teks
Pianka, Eric R.
Harper & Row , 1988
Buku Teks