Angkanavisal, N., K. Budsaba, and A. Volodin. “Asymptotic Confidence Ellipses of Parameters for the Beta-Poisson Dose-Response Model”. Thailand Statistician, vol. 10, no. 1, May 2015, pp. 15-39, https://ph02.tci-thaijo.org/index.php/thaistat/article/view/34230.