Nino B. Cocchiarella. A substitution free axiom set for second order logic. Notre Dame Journal of Formal Logic, 10(1):18-30, 1969. [doi]
@article{Cocchiarella69-0,
title = {A substitution free axiom set for second order logic},
author = {Nino B. Cocchiarella},
year = {1969},
doi = {10.1305/ndjfl/1093893584},
url = {http://dx.doi.org/10.1305/ndjfl/1093893584},
researchr = {https://researchr.org/publication/Cocchiarella69-0},
cites = {0},
citedby = {0},
journal = {Notre Dame Journal of Formal Logic},
volume = {10},
number = {1},
pages = {18-30},
}