@article{PismaZhETF.64.641,
    title = {Singularity of the vortex density of states in d-wave superconductors},
    author = {Kopnin, N. B. and Volovik, G. E.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {64},
    issue = {9},
    pages = {641},
    year = {1996},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_14991.shtml},
}