Downes, William
Cambridge University Press, 2003
eBooks
New York : Cambridge University Press
Majalah, Jurnal, Buletin
Malmstrom, Jean
Hayden Book Company, 1965
Buku Teks SO
Weatherall, Ann, 1964-
Routledge, 2002
Buku Teks
edited by Susan Ehrlich, Miriam Meyerhoff, and Janet Holmes
Wiley Blackwell, 2017
Buku Teks