Born: 22 Feb 1849 in Tula, Russia
Died: 27 Feb 1915 in Petrograd (now St. Petersburg), Russia
See a Russian article from the Brokhaus & Efron Dictionary
Sonin worked on special functions, in particular cylindrical functions. He also worked on the Euler- Maclaurin summation formula.
Other topics Sonin studied included Bernoulli polynomials and approximate computation of definite integrals, continuing Chebyshev's work on numerical integration.
Together with A A Markov, Sonin prepared a two volume edition of Chebyshev's works in French and Russian.
List of References
Article by: J.J. O'Connor and E.F. Robertson
Source: MacTutor History of Mathematics archive