S. BALASUBRAMANIAM, M. SINGH, G. R. GOWANE, and S. KUMAR, “Estimate of genetic and non-genetic parameters and trends for age at first calving in Sahiwal cows”, Indian J of Anim Sci, vol. 83, no. 9, Sep. 2013, doi: 10.56093/ijans.v83i9.33033.