Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1987_41_1_a8, author = {A. E. Andreev}, title = {The complexity of the realization of subdefinite matrices by gate schemes}, journal = {Matemati\v{c}eskie zametki}, pages = {77--86}, publisher = {mathdoc}, volume = {41}, number = {1}, year = {1987}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1987_41_1_a8/} }
A. E. Andreev. The complexity of the realization of subdefinite matrices by gate schemes. Matematičeskie zametki, Tome 41 (1987) no. 1, pp. 77-86. http://geodesic.mathdoc.fr/item/MZM_1987_41_1_a8/