Enoch Stumpf, S. (1971). History and problems. McGraw Hill.
Cita Chicago Style (17a ed.)Enoch Stumpf, Samuel. History and Problems. New York, Estados Unidos: McGraw Hill, 1971.
Cita MLA (9a ed.)Enoch Stumpf, Samuel. History and Problems. McGraw Hill, 1971.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.