1. Agrawal, P. C., Biswas, S., Gokhale, G. S., Ivengar, V. S., Kunte, P. K., Manchanda, R. K., and Sreekantan, B. V.: 1969a, in L. Gratton (ed.), ?Non Solar X-Ray and ?-Ray Astronomy?,IAU Symp..37, Reidel, Dordrecht.
2. Agrawal, P. C., Biswas, S., Gokhale, G. S., Iyengar, V. S., Kunte, P. K., Manchanda, R. K., and Sreekantan, B. V.: 1969b,Nature 224, 51.
3. Agrawal, P. C., Biswas, S., Gokhale, G. S., Iyengar, V. S., Kunte, P. K., Manchanda, R. K., and Sreekantan, B. V.: 1970,Proc. XIth International Conf. on Cosmic Rays, Budapest, Aug.?Sept. 1969, Acta Physica Acad. Scien. Hung. 29, Suppl. 1, 277.
4. Burginyon, G. A., Grader, R. J., Hill, R. W., Hiltner, W. A., Mannery, E. J., Price, R. E., Rodriques, R., Seward, F. D., and Swift, C. D.: 1970, LRL Preprint, to appear inAstrophys. J..
5. Buselli, G., Clancy, M. C., Davison, P. J. N., Edwards, P. J., McCracken, K. G., and Thomas, R. M.: 1968,Nature 219, 1124.