@article{PA_2017_6_2_a4,
     author = {Kwara Nantomah},
     title = {Monotonicity and convexity properties of the {Nielsen's} $\beta$-function},
     journal = {Problemy analiza},
     pages = {81--93},
     publisher = {mathdoc},
     volume = {6},
     number = {2},
     year = {2017},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PA_2017_6_2_a4/}
}