Bazalii, B. V. “On One Proof of the Classical Solvability of the Hele-Shaw Problem With Free Boundary”.
Ukrains’kyi Matematychnyi Zhurnal 50, no. 11 (November 25, 1998): 1452–1462. Accessed April 14, 2025.
https://umj.imath.kiev.ua/index.php/umj/article/view/4797.