Crowell-Collier. Editores. Collier's Encyclopedia. Vol XII.
Cita Chicago (17th ed.)Crowell-Collier. Editores. Collier's Encyclopedia. Vol XII. [s.l.] : Crowell-Collier.
Cita MLA (8th ed.)Crowell-Collier. Editores. Collier's Encyclopedia. Vol XII.
Atenció: Aquestes cites poden no estar 100% correctes.