1. Astrup Micro Equipment Bulletin No. 21917+;Astrup,1960
2. Simple and precise micromethod for EDTA titration of calcium;Copp;J. Lab. Clin. Med.,1963
3. A simplified protometric method for the determination of citric acid in biological fluids;Ettinger;J. Biol. Chem.,1952
4. The relation of citrate and calcium metabolism;Freeman,1961
5. Determination of serum proteins by means of the biuret reaction;Gornall;J. Biol. Chem.,1949