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@article{IVM_1962_1_a8, author = {\"U. G. Lumiste and L. A. Tuulmets}, title = {Minimal congruences $V_3$ in the {Euclidean} space $R_4$}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {74--82}, publisher = {mathdoc}, number = {1}, year = {1962}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1962_1_a8/} }
Ü. G. Lumiste; L. A. Tuulmets. Minimal congruences $V_3$ in the Euclidean space $R_4$. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 1 (1962), pp. 74-82. http://geodesic.mathdoc.fr/item/IVM_1962_1_a8/