Wheeler, James O.
John Wiley & Sons, 1986
Buku Teks SO
Getis, Arthur
McGraw-Hill, 2000
Buku Teks SO
Moore, W.G.
London : Penguin Books, 1984,
Buku Referensi
Hall, Tim, 1968-
Routledge, 2018
Buku Teks SO
Getis, Arthur
McGraw-Hill Higher Education, 2009
Buku Teks SO