Juaristi, Eusebio, author
John Wiley & Sons, 1991
Buku Teks
Crippen, G. M.
Research Studies Press, 1981
Buku Teks
Wade, William R., author
Prentice-Hall, 1995
Buku Teks
Raykov, Tenko, author
Routledge, Taylor & Francis Group, 2008
Buku Teks
Hildebrand, Francis Begnaud, author
Tata McGraw-Hill, 1974
Buku Teks