@article{MZM_2010_87_6_a10,
     author = {I. Kh. Sabitov},
     title = {On the {Extrinsic} {Curvature} and the {Extrinsic} {Structure} of {Normal} {Developable} $C^1$ {Surfaces}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {900--906},
     publisher = {mathdoc},
     volume = {87},
     number = {6},
     year = {2010},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2010_87_6_a10/}
}