Rahman, H. Z., M. R. Islam, A. Salam, M. M. Bhuiyan, A. N. Rizvi, K. K. Barman, and S. M. Alam. “Association of Serum Testosterone Level With Depression in Parkinson’s Disease”. Bangladesh Journal of Neuroscience, vol. 27, no. 2, Jan. 2014, pp. 57-63, doi:10.3329/bjn.v27i2.17541.