Strahler, Arthur N., author
John Wiley & Sons, 1989
Buku Teks
Strahler, Arthur N., author
John Wiley & Sons, 2004
Buku Teks
Hidore, John J., author
Scott, Foresman, 1974
Buku Teks
by R.D. Thompson ... [et al.]
Longman, 1993
Buku Teks
De Blij, Harm J., author
John Wiley & Sons, 1996
Buku Referensi