Getis, Arthur, author
McGraw-Hill Higher Education, 2009
Buku Teks
Northam, Ray M., author
John Wiley & Sons, 1979
Buku Teks
Burton, Rosemary, author
Pitman, 1995
Buku Teks
Unwin, Tim, author
Longman Scientific & Technical, 1992
Buku Teks
Thatcher, W.S., author
English University Press, 1957
Buku Teks