1. E, L and A values;Fried;Trans. 8th Int. Congr. Soil Sci.,1964
2. The fate of 18O-labelled phosphate in soil/plant systems;Larsen;Plant Soil,1989
3. Analysis of nitrogen, carbon, and oxygen isotope ratios by optical emission spectrometry;Middelboe,1991
4. The stability of oxygen-18 labelled phosphate in aqueous solution;Saaby;Appl. Radiat. Isot.,1989
5. Delabelling of 18O-enriched phosphate added to soil as a function of biological activity in the soil;Saaby,1991