@article{AMLG_1971__9_137790,
     author = {Kurt Sch\"utte and John N. Crossley},
     title = {Non-Uniqueness at ... in {Kleene's} {O.}},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {95--101},
     publisher = {mathdoc},
     volume = {9},
     year = {1971},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1971__9_137790/}
}