@article{RM_1988_43_3_a21,
     author = {V. G. Vinokurov and B. A. Rubshtein and A. L. F\"edorov},
     title = {Normal subgroupoids and extensions of measured groupoids},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {231--232},
     publisher = {mathdoc},
     volume = {43},
     number = {3},
     year = {1988},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1988_43_3_a21/}
}