Preston, D. R., & Shuy, R. W. (1988). Varieties of American English: Teacher's handbook. Washington, DC.: Department of state.
Dyfyniad Arddull ChicagoPreston, Dennis R., và Roger W. Shuy. Varieties of American English: Teacher's Handbook. Washington, DC.: Department of state, 1988.
Dyfyniad MLAPreston, Dennis R., và Roger W. Shuy. Varieties of American English: Teacher's Handbook. Washington, DC.: Department of state, 1988.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.