@article{AM2_1971__7_136236,
     author = {S.P. AVANN},
     title = {The {Lattice} of {Natural} {Orders} {(Short} {Communication)}},
     journal = {Aequationes mathematicae},
     pages = {117--117},
     publisher = {mathdoc},
     volume = {7},
     year = {1971},
     url = {http://geodesic.mathdoc.fr/item/AM2_1971__7_136236/}
}