Alan Ross Anderson, Nuel Belnap. Modalities in Ackermann s Rigorous Implication . Journal of Symbolic Logic, 24(2):107-111, 1959.
@article{AndersonB59,
title = {Modalities in Ackermann s Rigorous Implication },
author = {Alan Ross Anderson and Nuel Belnap},
year = {1959},
researchr = {https://researchr.org/publication/AndersonB59},
cites = {0},
citedby = {0},
journal = {Journal of Symbolic Logic},
volume = {24},
number = {2},
pages = {107-111},
}