Strahler, Arthur N.
John Wiley & Sons, 1983
Buku Teks
Strahler, Arthur N.
John Wiley & Sons, 1975
Buku Teks
Trewartha, Glenn T.
McGraw-Hill, 1967
Buku Teks
De Blij, Harm J.
John Wiley & Sons, 1993
Buku Teks
oleh Glenn T. Trewartha [and others]
McGraw-Hill, 1977
Buku Teks