Trewartha, Glenn T., author
McGraw-Hill, 1967
Buku Teks
Petersen, James F., author
Brooks/Cole Cengage Learning, 2012
Buku Teks
Trewartha, Glenn T., author
McGraw-Hill, 1967
Buku Teks
De Blij, Harm J., author
John Wiley and Sons, 1993
Buku Teks
oleh Glenn T. Trewartha [and others]
McGraw-Hill, 1977
Buku Teks