Dyfyniad APA

Fredrickson, B. (2009). Positivity (First edition.). Three Rivers Press.

Dyfyniad Arddull Chicago

Fredrickson, Barbara. Positivity. First edition. New York: Three Rivers Press, 2009.

Dyfyniad MLA

Fredrickson, Barbara. Positivity. First edition. Three Rivers Press, 2009.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.