BAKOSURTANAL, 2008
Buku Teks
Getis, Arthur
McGraw-Hill Higher Education, 2009
Buku Teks
by Les Rowntree ... [and others]
Prentice-Hall, 2011
Buku Teks
Trewartha, Glenn T.
McGraw-Hill, 1967
Buku Teks
Unwin, Tim
Longman Scientific & Technical, 1992
Buku Teks