@article{MOMA_1997__123_1_178778,
     author = {Norman R. Reilly and Shuhua Zhang},
     title = {Commutativity of {Operators} on the {Lattice} of {Existence} {Varieties.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {337--364},
     publisher = {mathdoc},
     volume = {123},
     number = {1},
     year = {1997},
     zbl = {0870.20042},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1997__123_1_178778/}
}