@article{GDZPPN00204322X,
title = {Substitutionless Predicate Logic with Identity.},
journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
volume = {7},
year = {1964},
pages = {102-121},
zbl = {0158.24603},
url = {http://dml.mathdoc.fr/item/GDZPPN00204322X}
}
Monk, Donald. Substitutionless Predicate Logic with Identity.. Archiv für mathematische Logik und Grundlagenforschung, Tome 7 (1964) pp. 102-121. http://gdmltest.u-ga.fr/item/GDZPPN00204322X/