-. American Association University Professors Bulletin, Vol. 41, Number 2, Summer 1955. American Association University Professors.
Dyfyniad Arddull Chicago-. American Association University Professors Bulletin, Vol. 41, Number 2, Summer 1955. American Association University Professors.
Dyfyniad MLA-. American Association University Professors Bulletin, Vol. 41, Number 2, Summer 1955. American Association University Professors.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.