1. Photometric determination of calcium via precipitation of its naphtylhydroxamate;Amin;Chem. Analyst,1957
2. Reference is taken from Amin;Beck;Mikrochemie ver. Mikrochim. Acta 1951,1957
3. Micro-Calcium Bestimmung im Blute;Nordbö;Biochem. Z.,1932
4. Improvements in the methods for calcium determination in biological material;Wang;J. biol. Chem.,1935