@article{RM_1978_33_2_a0,
     author = {M. A. Shubin},
     title = {Almost periodic functions and partial differential operators},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {1--52},
     publisher = {mathdoc},
     volume = {33},
     number = {2},
     year = {1978},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1978_33_2_a0/}
}