Shtertser, N., Y. Tsap, and Z. Akhtemov. “On the Quality of Sunspot Images from Observations at the STT-2 of CrAO”. Acta Astrophysica Taurica, vol. 6, no. 1, Mar. 2025, pp. 31-34, https://astrophysicatauricum.org/index.php/aat/article/view/107.