Kanguzhin, B., Zhapsarbayeva, L. and Madibaiuly, Z. 2019. Lagrange formula for differential operators and self-adjoint restrictions of the maximal operator on a tree . Eurasian Mathematical Journal. 10, 1 (Mar. 2019), 16–29. DOI:https://doi.org/10.32523/2077-9879-2019-10-1-16-29.