Федак, Іван Васильович. “SOME SUBSTANDARD APPLICATIONS OF THE COSINES THEOREM”. PRECARPATHIAN BULLETIN OF THE SHEVCHENKO SCIENTIFIC SOCIETY. Number, no. 1(9) (March 7, 2019): 51–55. Accessed December 6, 2025. https://pvntsh.nung.edu.ua/index.php/number/article/view/285.