@article{VMJ_2003_5_4_a1,
     author = {E. K. Basaeva and A. G. Kusraev},
     title = {On the quasi-differential of a composition},
     journal = {Vladikavkazskij matemati\v{c}eskij \v{z}urnal},
     pages = {10--25},
     publisher = {mathdoc},
     volume = {5},
     number = {4},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMJ_2003_5_4_a1/}
}