@article{AMI_2013_41_a5,
     author = {Heiko Harborth},
     title = {On h-perfect numbers},
     journal = {Annales mathematicae et informaticae},
     pages = {57--62},
     publisher = {mathdoc},
     volume = {41},
     year = {2013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AMI_2013_41_a5/}
}