@article{DAN_1957_113_4_a15,
     author = {G. G. Slyusarev},
     title = {Optical systems with phase layers},
     journal = {Doklady Akademii Nauk},
     pages = {780--783},
     publisher = {mathdoc},
     volume = {113},
     number = {4},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_113_4_a15/}
}