@article{MZ_1968__103_170906,
     author = {Joachim Lambek},
     title = {A {Fixpoint} {Theorem} for complete {Categories.}},
     journal = {Mathematische Zeitschrift},
     pages = {151--161},
     publisher = {mathdoc},
     volume = {103},
     year = {1968},
     zbl = {0149.26105},
     url = {http://geodesic.mathdoc.fr/item/MZ_1968__103_170906/}
}