@article{AMI_2013_41_a21,
     author = {Clark Kimberling},
     title = {Problem proposals},
     journal = {Annales mathematicae et informaticae},
     pages = {271--274},
     year = {2013},
     volume = {41},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AMI_2013_41_a21/}
}