K. Shahzad, Z. Mohy-ud-Din, M. A. Chowdhry and D. Hussain
Pakistan Journal of Biological Sciences 1 ( 3 ): 237 - 240 , 1998
M. Aslam, D. Hussain and Y. Zafar
Pakistan Journal of Biological Sciences 3 ( 12 ): 2203 - 2205 , 2000