@article{GDZPPN002041707,
title = {Incomplete idempotent Schr\"oder quasigroups and related packing designs.},
journal = {Aequationes mathematicae},
volume = {52},
year = {1996},
pages = {100-114},
zbl = {0844.05027},
url = {http://dml.mathdoc.fr/item/GDZPPN002041707}
}
Zhu, L.; Bennett, F.E.; Wei, R. Incomplete idempotent Schröder quasigroups and related packing designs.. Aequationes mathematicae, Tome 52 (1996) pp. 100-114. http://gdmltest.u-ga.fr/item/GDZPPN002041707/