@article{MZM_1987_41_5_a11,
     author = {M. \`E. V\"aljas and \"U. G. Lumiste},
     title = {Isothermal hypersurfaces and three-dimensional {Dupin--Mannheim} hypercyclides},
     journal = {Matemati\v{c}eskie zametki},
     pages = {731--740},
     publisher = {mathdoc},
     volume = {41},
     number = {5},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1987_41_5_a11/}
}