@article{PA_2019_8_3_a9,
     author = {L. Matej{\'\i}\v{c}ka},
     title = {Proof of a conjecture on {Nielsen's} $\beta$-function},
     journal = {Problemy analiza},
     pages = {105--111},
     publisher = {mathdoc},
     volume = {8},
     number = {3},
     year = {2019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PA_2019_8_3_a9/}
}