A. U. Zafar, M. A. Qadeer, and S. Riazuddin, “STUDIES ON THE PRODUCTION OF SPORE CRYSTAL BY BACILLUS THURINGIENSIS CAMB 3-023 IN THE STIRRED FERMENTOR”, Pakistan Journal of Scientific & Industrial Research, vol. 46, no. 4, pp. 242–245, Aug. 2003.