Pervaiz, M. (1989). Covariance Matrix Estimation in Complex Surveys. test, 33(1), 130-138. doi: 10.21608/esju.1989.316528
Muhammad Khalid Pervaiz. "Covariance Matrix Estimation in Complex Surveys". test, 33, 1, 1989, 130-138. doi: 10.21608/esju.1989.316528
Pervaiz, M. (1989). 'Covariance Matrix Estimation in Complex Surveys', test, 33(1), pp. 130-138. doi: 10.21608/esju.1989.316528
Pervaiz, M. Covariance Matrix Estimation in Complex Surveys. test, 1989; 33(1): 130-138. doi: 10.21608/esju.1989.316528