@article{RM_1992_47_6_a1,
     author = {P. Loshak},
     title = {Canonical perturbation theory via simultaneous approximation},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {57--133},
     publisher = {mathdoc},
     volume = {47},
     number = {6},
     year = {1992},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1992_47_6_a1/}
}