@article{JRAM_1978__0299_0300_151990,
     author = {H. Hasse and G.D. Prichett},
     title = {The determination of all four-digit {Kaprekar} constants.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {113--124},
     publisher = {mathdoc},
     volume = {0299_0300},
     year = {1978},
     zbl = {0367.10006},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1978__0299_0300_151990/}
}