Dyfyniad APA

Johnson. Toxic Airs. University of Pittsburgh Press.

Dyfyniad Arddull Chicago

Johnson. Toxic Airs. University of Pittsburgh Press.

Dyfyniad MLA

Johnson. Toxic Airs. University of Pittsburgh Press.

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