@article{TMF_1972_10_1_a7,
     author = {K. S. Matviichuk},
     title = {Dependence of reduced density matrices on the boundary conditions},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {85--101},
     publisher = {mathdoc},
     volume = {10},
     number = {1},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1972_10_1_a7/}
}