Gary H. Merrill. A free logic with intensions as possible values of terms. J. Philosophical Logic, 4(4):293-326, 1975. [doi]
@article{Merrill75,
title = {A free logic with intensions as possible values of terms},
author = {Gary H. Merrill},
year = {1975},
doi = {10.1007/BF00262041},
url = {http://dx.doi.org/10.1007/BF00262041},
researchr = {https://researchr.org/publication/Merrill75},
cites = {0},
citedby = {0},
journal = {J. Philosophical Logic},
volume = {4},
number = {4},
pages = {293-326},
}