Citation:
V. P. Burskii, A. S. Zhedanov, “Boundary value problems for string equation, Poncelet problem, and Pell–Abel equation: links and relations”, Proceedings of the Fourth International Conference on Differential and Functional-Differential Equations (Moscow, August 14–21, 2005). Part 2, CMFD, 16, PFUR, M., 2006, 5–9; Journal of Mathematical Sciences, 149:5 (2008), 1483–1487