Dyfyniad APA

(1981). World English. Washington, DC.: United states Department of state.

Dyfyniad Arddull Chicago

World English. Washington, DC.: United states Department of state, 1981.

Dyfyniad MLA

World English. Washington, DC.: United states Department of state, 1981.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.