DIN SPEC 1092
DIN SPEC 1092 Fertilizers - Extraction of phosphorus soluble in 2 % formic acid; German version CEN/TS 15919:2009
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 02/01/2010
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 02/01/2010