Karymsakov Қ. У. Т., Karazhanova К. Д., and Iisova И. А. . “Variation Methods in Solving Positional Problems”. Рroblems of Engineering and Professional Education, vol. 62, no. 3, Nov. 2022, p. 45, doi:10.32523/2220-685X-2021-62-3-45.