@article{ZNSL_2007_342_a0,
     author = {V. M. Babich},
     title = {Space-time ray method and quasiphotons},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {5--13},
     year = {2007},
     volume = {342},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2007_342_a0/}
}