@article{Kharlampovich_2008,
    doi = {10.1007/s00224-008-9153-7},
    url = {https://doi.org/10.1007%2Fs00224-008-9153-7},
    year = {2008},
    month = {oct},
    publisher = {Springer Science and Business Media {LLC}},
    volume = {47},
    number = {1},
    pages = {250--258},
    author = {O. Kharlampovich and I. G. Lysënok and A. G. Myasnikov and N. W. M. Touikan},
    title = {The Solvability Problem for Quadratic Equations over~Free Groups is {NP}-Complete},
    journal = {Theory of Computing Systems}
}

@article{Kharlampovich_2008, doi = {10.1007/s00224-008-9153-7}, url = {https://doi.org/10.1007%2Fs00224-008-9153-7}, year = {2008}, month = {oct}, publisher = {Springer Science and Business Media {LLC}}, volume = {47}, number = {1}, pages = {250--258}, author = {O. Kharlampovich and I. G. Lysënok and A. G. Myasnikov and N. W. M. Touikan}, title = {The Solvability Problem for Quadratic Equations over~Free Groups is {NP}-Complete}, journal = {Theory of Computing Systems} }