@article{PFMT_2020_4_a2,
     author = {S. S. Girgel},
     title = {Solutions of the wave equation in parabolic rotary coordinates. {II.} {3D} {Tricomi--Kummer} light beams and other beams with the continuous angular index},
     journal = {Problemy fiziki, matematiki i tehniki},
     pages = {20--24},
     publisher = {mathdoc},
     number = {4},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PFMT_2020_4_a2/}
}