Gatebe, C. K. (Nairobi Univ. Kenya)
Tyson, P. D. (Witwatersrand Univ. Johannesburg, South Africa)
Annegarn, H. (Witwatersrand Univ. Johannesburg, South Africa)
Piketh, S. (Witwatersrand Univ. Johannesburg, South Africa)
Helas, G. (Max-Planck-Inst. fuer Chemie Mainz, Germany)