@article{MZM_1991_50_5_a13,
     author = {E. V. Ferapontov},
     title = {Equations of hydrodynamic type from the point of view of the theory of webs},
     journal = {Matemati\v{c}eskie zametki},
     pages = {97--108},
     year = {1991},
     volume = {50},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1991_50_5_a13/}
}