@book{13678,
	author = {Symposium on the Use of Isotopes in Studies of Nitrogen Metabolism in the Soil-Plant-Animal System, and International Atomic Energy Agency.},
	title = {Isotope studies on the nitrogen chain :},
	publisher = {International Atomic Energy Agency,},
	year = {1968.},
	series = {Proceedings series},
	address = {Vienna,}
}