[6] Wallis. Ind. Jour. Med. Res., 1917, 4, 797.
[7] Le Roy. Comptes rend., 1916, 163, 226.
[8] Winkler. Zeit. angew. Chem., 1915, 28, 22.
[9] Rideal, E. K. and Evans. Analyst, 1913, 38, 353.
[10] J. Amer. Pub. Health Assoc. 1915, 5, 921.
[11] Thresh. Internat. Congress Appl. Chem., 1908.
[12] Walker. Jour. Roy. Inst. Pub. Health, Jan., 1911.