The Hague, 1972
Buku Teks
Fishman, Joshua A., author
Newbury House Publishers, 1972
Buku Teks
edited by Basic concepts theories and problems alternative approaches Selected studies and applications
Mouton, 1972
Buku Teks SO
Downes, William, author
Cambridge University Press, 2003
eBooks
Malmstrom, Jean, author
Hayden Book Company, 1965
Buku Teks SO