Atkinson, Paul, author
Routledge, 1994
Buku Teks
Antonius C.G.M. Robben, Jeffrey A. Sluka.
Wiley-Blackwell, 2012
Buku Teks
Spradley, James P.
Halt, Rinehart and Winston, 1979
Buku Teks
Hammersley, Martyn, author
Longman , 1990
Buku Teks
Heider, Karl G., author
University of Texas Press, 1976.
Buku Teks