1. Effect of sulfur application on sulfur-oxidising Bacteria and yield of two leguminous crops;Badawy;ZBL Bakt. II Natur.,1978
2. The Sulphur status of eastern canadian prairie soils: sulphur response and requirements of alfalfa (Medicago sativa L.), rape (Brassica napas L.) and barley (Hordeum vulgare L.;Bailey;Can. J. Soil Sci.,1986
3. Production, marketing, and use of potassium fertilizers;Barber,1985
4. Einfluss von Schwefel- und Stickstoffdüngung auf den Kornertrag von Winterraps in ökologischem Anbau;Becker,2011
5. Map: Gehalte an organischer Substanz in Oberböden Deutschlands;BGR,2007