Dewi, Yuliani .S., et al. “Comparison of Nelder Mead and BFGS Algorithms on Geographically Weighted Multivariate Negative Binomial”. International Journal on Advanced Science, Engineering and Information Technology, vol. 9, no. 3, May 2019, pp. 979-87, doi:10.18517/ijaseit.9.3.6932.