@article{Grigorchuk_1997,
    doi = {10.1007/bf02471762},
    url = {https://doi.org/10.1007%2Fbf02471762},
    year = {1997},
    month = {jan},
    publisher = {Springer Science and Business Media {LLC}},
    volume = {3},
    number = {1},
    pages = {51--89},
    author = {R. Grigorchuk and P. De La Harpe},
    title = {On problems related to growth, entropy, and spectrum in group theory},
    journal = {Journal of Dynamical and Control Systems}
}

@article{Grigorchuk_1997, doi = {10.1007/bf02471762}, url = {https://doi.org/10.1007%2Fbf02471762}, year = {1997}, month = {jan}, publisher = {Springer Science and Business Media {LLC}}, volume = {3}, number = {1}, pages = {51--89}, author = {R. Grigorchuk and P. De La Harpe}, title = {On problems related to growth, entropy, and spectrum in group theory}, journal = {Journal of Dynamical and Control Systems} }