Silvio Valentini. Extensionality Versus Constructivity. Math. Log. Q., 48(2):179-187, 2002. [doi]
@article{Valentini02,
title = {Extensionality Versus Constructivity},
author = {Silvio Valentini},
year = {2002},
doi = {10.1002/1521-3870(200202)48:2<179::AID-MALQ179>3.0.CO;2-K},
url = {http://dx.doi.org/10.1002/1521-3870(200202)48:2<179::AID-MALQ179>3.0.CO;2-K},
researchr = {https://researchr.org/publication/Valentini02},
cites = {0},
citedby = {0},
journal = {Math. Log. Q.},
volume = {48},
number = {2},
pages = {179-187},
}