The Greatest Extension of S4 into which Intuitionistic Logic is Embeddable
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\begin{bibtex} @article{DBLP:journals/sLogica/Zakharyaschev97,
author = {Michael Zakharyaschev},
title = {The Greatest Extension of S4 into which Intuitionistic Logic
is Embeddable},
journal = {Studia Logica},
volume = {59},
number = {3},
year = {1997},
pages = {345-358},
bibsource = {DBLP, http://dblp.uni-trier.de}
}
\end{bibtex}
