1. P. Langevin. Selected Works, Moscow-Leningrad, Izd. Akad. Nauk SSSR(1960).
2. V. N. Tsvetkov. Kolloidn. Zh. 41:197 (1949).
3. W. C. Elmor. Phys. Rev. 60:593 (1941).
4. E. Lourila, Ann. Acad. Sci. Fennicae, Ser. A Vol. 34 (1959); Vol. 70 (1961).
5. H. E. Rose. Chem. Prod. 18:375 (1955).