@article{ZNSL_1975_50_a4,
     author = {E. V. Podsypanin},
     title = {On the representation of integers by a~system of additive positive quadratic forms},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {137--155},
     year = {1975},
     volume = {50},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1975_50_a4/}
}