@article{UZERU_2006_1_a3,
     author = {A. B. Grigorian},
     title = {Algebraic multigrid preconditioner for elliptic problems with mixed type boundary conditions. {I.} {Two-grid} preconditioners},
     journal = {Proceedings of the Yerevan State University. Physical and mathematical sciences},
     pages = {37--48},
     publisher = {mathdoc},
     number = {1},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZERU_2006_1_a3/}
}