Richter, A. K., van Hollebeke, M. A. I., Hsieh, K. C., Denskat, K. U., Keppler, E., McDonald, F. B., et al. (1979). Energetic particles at interplanetary shock waves: the April 29, 1978 event. In Proc. 16th International Cosmic Ray Conference, Kyoto, Japan (pp. 312-317).