@article{GDZPPN002318571,
title = {Perfect Elements in the Free Modular Lattices.},
journal = {Mathematische Annalen},
volume = {250},
year = {1980},
pages = {95-100},
zbl = {0443.06005},
url = {http://dml.mathdoc.fr/item/GDZPPN002318571}
}
Dlab, Vlastimil; Ringel, Claus Michael. Perfect Elements in the Free Modular Lattices.. Mathematische Annalen, Tome 250 (1980) pp. 95-100. http://gdmltest.u-ga.fr/item/GDZPPN002318571/