@article{SM_2017_208_10_a5,
     author = {V. M. Manuilov},
     title = {Pairs of operators with equal defect from unitarity and their relative index},
     journal = {Sbornik. Mathematics},
     pages = {1523--1534},
     publisher = {mathdoc},
     volume = {208},
     number = {10},
     year = {2017},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2017_208_10_a5/}
}