1. Schönberg and BadranJ.A.C.S., 1951,73, 2960;
2. Mukerjee and SeshadriProc. Ind. Acad. Sci., 1952,35 A, 326.
3. Dharet al. Journ. Sci. Ind. Res., 1955,14 B, 73;
4. Maheshet al. Proc. Ind. Acad. Sci., 1954,39 A, 166.
5. Baker and SimmondsJ.C.S-, 1940, 1373.