Dyfyniad APA

McDonald, J. C. (1981). Four pillars of occupational health.

Dyfyniad Arddull Chicago

McDonald, J C. Four Pillars of Occupational Health. 1981.

Dyfyniad MLA

McDonald, J C. Four Pillars of Occupational Health. 1981.

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