edited by Philip L. Wagner, Marvin W. Mikesell
University of Chicago Press, 1962
Buku Referensi
Warf, Barney, editor
Springer, 2012
eBooks
Martin, A.W.
Rigby Limited, 1962
Buku Teks
Trewartha, Glenn T.
McGraw-Hill, 1967
Buku Teks
Kim Uichol [et.all.]
Springer, 2006
Buku Teks