@article{PFMT_2020_3_a1,
     author = {S. S. Girgel},
     title = {Solutions of the wave equation in parabolic rotary coordinates. {I.} {3D} {Kummer--Kummer} light beams with the continuous angular index},
     journal = {Problemy fiziki, matematiki i tehniki},
     pages = {13--17},
     publisher = {mathdoc},
     number = {3},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PFMT_2020_3_a1/}
}