Mazėtis, Edmundas, and Grigorijus Melničenko. “A Rational Sine and Cosine of the Angles of a Triangle”. Lietuvos matematikos rinkinys 54, no. B (December 20, 2013): 151–154. Accessed April 29, 2024. https://www.journals.vu.lt/LMR/article/view/17182.