Isotope studies on the nitrogen chain : Proceedings of the symposium / Symposium on the Use of Isotopes in Studies of Nitrogen Metabolism in the Soil-Plant-Animal System, Vienna, 1967. International Atomic Energy Agency. Food and Agriculture Organization of the United Nations. Joint Commission on Applied Radioactivity. Radioactive tracers in agriculture. Nitrogen Metabolism. S589.5 .S92 1967 539.74 INI Includes bibliographical references and index Vienna, International Atomic Energy Agency, 1968. 1968. 1968 Text 343 p. : eng engfrerus Proceedings series Proceedings series (International Atomic Energy Agency)