%0 Journal Article
%A R. M. Geidel'man
%T Multidimensional ruled surfaces with holonomic families of $L^{\hat a}_s$-planes, and focal transforms of a~surface
%J Izvestiâ vysših učebnyh zavedenij. Matematika
%D 1975
%P 97-100
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IVM_1975_1_a14/
%G ru
%F IVM_1975_1_a14