@article{AM2_1977__16_136685,
     author = {Joel Berman},
     title = {Distributive lattices with an additional unary operation.},
     journal = {Aequationes mathematicae},
     pages = {165--172},
     publisher = {mathdoc},
     volume = {16},
     year = {1977},
     zbl = {0395.06007},
     url = {http://geodesic.mathdoc.fr/item/AM2_1977__16_136685/}
}