Trewartha, Glenn T.
McGraw-Hill, 1967
Buku Teks
Strahler, Arthur N.
John Wiley & Sons, 1975
Buku Teks
Petersen, James F.
Brooks/Cole Cengage Learning, 2012
Buku Teks
Trewartha, Glenn T.
McGraw-Hill, 1967
Buku Teks
De Blij, Harm J.
John Wiley & Sons, 1993
Buku Teks