Fontaine, E. O. Collier's Encyclopedia: FER-GEO.
Cita Chicago (17th ed.)Fontaine, Everett O. Collier's Encyclopedia: FER-GEO.
Cita MLA (8th ed.)Fontaine, Everett O. Collier's Encyclopedia: FER-GEO.
Atenció: Aquestes cites poden no estar 100% correctes.