@article{DE_1980_16_4_a2,
     author = {I. Jo and N. La\v{z}eti\'c},
     title = {Estimate of the difference of derivatives of partial sums of decompositions corresponding to two arbitrary nonnegative selfadjoint extensions of two operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {598--619},
     publisher = {mathdoc},
     volume = {16},
     number = {4},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1980_16_4_a2/}
}