Dyfyniad APA

National Fertilizer Development Center. (1973). Fertilizer trends. Washington, D.C: National Fertilizer Development Center.

Dyfyniad Arddull Chicago

National Fertilizer Development Center. Fertilizer Trends. Washington, D.C: National Fertilizer Development Center, 1973.

Dyfyniad MLA

National Fertilizer Development Center. Fertilizer Trends. Washington, D.C: National Fertilizer Development Center, 1973.

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