@article{IM2_1980_14_3_a3,
     author = {V. F. Safonov},
     title = {The regularization method for singularly perturbed systems of nonlinear differential equations},
     journal = {Izvestiya. Mathematics },
     pages = {571--596},
     publisher = {mathdoc},
     volume = {14},
     number = {3},
     year = {1980},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1980_14_3_a3/}
}