Barker, S. F. (1974). Elements of logic (2nd ed.). McGraw-Hill.
Dyfyniad Arddull ChicagoBarker, Stephen Francis. Elements of Logic. 2nd ed. New York: McGraw-Hill, 1974.
Dyfyniad MLABarker, Stephen Francis. Elements of Logic. 2nd ed. McGraw-Hill, 1974.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.