Obtaining granular NPK fertilizers from single superphosphate and ureaAasamäe, Ernst; Arumeel, Edgar; Einard, Marve; Veiderma, MihkelFertilizer research1993 / p. 161-167

Obtaining NPK fertilizers using decomposition of phosphate rock by sulphuric rock by sulphuric acidAasamäe, Ernst; Kudrjavtseva, Jelena; Einard, MarveFertilizer research1993 / p. 197-202