@article{MZ_1984__188_173546,
     author = {L.J. Jr. Ratliff},
     title = {Essential {Sequences} {Over} an {Ideal} and {Essential} {Cograde.}},
     journal = {Mathematische Zeitschrift},
     pages = {383--396},
     publisher = {mathdoc},
     volume = {188},
     year = {1984},
     zbl = {0534.13001},
     url = {http://geodesic.mathdoc.fr/item/MZ_1984__188_173546/}
}