@article{MT_1985_6_a1,
     author = {H. Ya. Bulgakov and S. K. Godunov},
     title = {Calculation of positive definite solutions of the {Lyapunov} equation},
     journal = {Matemati\v{c}eskie trudy},
     pages = {17--38},
     publisher = {mathdoc},
     volume = {6},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_1985_6_a1/}
}