@book{ international1968iaea, title={Experimental Techniques for Co-ordinated Field Fertility Experiments Using Isotopically Labelled Fertilizers (Vienna, 27 Nov. - 1 Dec. 1967)}, series={TECDOC Series}, number={113}, year={1968}, url={http://www.dgdingfa.net/publications/354/experimental-techniques-for-co-ordinated-field-fertility-experiments-using-isotopically-labelled-fertilizers-vienna-27-nov-1-dec-1967}, publisher={INTERNATIONAL ATOMIC ENERGY AGENCY}, address={Vienna} }