@article{GDZPPN002026236,
title = {The Lattice of Natural Partial Orders.},
journal = {Aequationes mathematicae},
volume = {8},
year = {1972},
pages = {95-102},
zbl = {0251.06005},
url = {http://dml.mathdoc.fr/item/GDZPPN002026236}
}
Avann, S.P. The Lattice of Natural Partial Orders.. Aequationes mathematicae, Tome 8 (1972) pp. 95-102. http://gdmltest.u-ga.fr/item/GDZPPN002026236/