@article{ZNSL_2008_353_a1,
     author = {Yu. D. Burago and S. G. Malev and D. I. Novikov},
     title = {A direct proof of {Gromov's} theorem},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {14--26},
     publisher = {mathdoc},
     volume = {353},
     year = {2008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2008_353_a1/}
}