1. Agrawal, S. P. and Bercovitch, M.: 1983,Proc. 18th Int. Cosmic Ray Conf., Bangalore 3, 316.
2. Agrawal, S. P. and Singh, R. L.: 1975,Proc. 14th Int. Cosmic Ray Conf., M�nchen 4, 11293.
3. Ahluwalia, H. S.: 1988,Geophys. Res. Letters 15, 287.
4. Ahluwalia, H. S. and Riker, J. F.: 1985,Proc. 19th Int. Cosmic Ray Conf., La Jolla 5, 116.
5. Ananth, A. G.: 1975, ?The Time Variations of Cosmic Ray Intensity?, Ph.D. Thesis.