@article{ZNSL_1977_72_a17,
     author = {B. S. Tsirel'son},
     title = {Addendum to the article on natural modification},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {202--211},
     publisher = {mathdoc},
     volume = {72},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1977_72_a17/}
}