Barr, J. (1971). The environmental handbook: Action guide for the U.K. London: A Ballantine Friends of the Earth Book.
Dyfyniad Arddull ChicagoBarr, John. The Environmental Handbook: Action Guide for the U.K. London: A Ballantine Friends of the Earth Book, 1971.
Dyfyniad MLABarr, John. The Environmental Handbook: Action Guide for the U.K. London: A Ballantine Friends of the Earth Book, 1971.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.