Levinson,Norman. (1940). American Mathematical Society Colloquium Publications Volum XXVI (1940.). American Mathematical Society.
Dyfyniad Arddull ChicagoLevinson,Norman. American Mathematical Society Colloquium Publications Volum XXVI. 1940. New York: American Mathematical Society, 1940.
Dyfyniad MLALevinson,Norman. American Mathematical Society Colloquium Publications Volum XXVI. 1940. American Mathematical Society, 1940.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.