Spack, R. (1998). Guidelines: A cross-cultural reading/writing text (2nd ed.). New York: St. Martin's Press.
Dyfyniad Arddull ChicagoSpack, Ruth. Guidelines: A Cross-cultural Reading/writing Text. 2nd ed. New York: St. Martin's Press, 1998.
Dyfyniad MLASpack, Ruth. Guidelines: A Cross-cultural Reading/writing Text. 2nd ed. New York: St. Martin's Press, 1998.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.