@article(etm,
title = "Extra Theory Morphisms for Institutions:
logical semantics for multi-paradigm languages",
author = "{R\u{a}zvan} Diaconescu",
volume = 6,
number = 4,
year = 1998,
journal = "Applied Categorical Structures",
pages = "427--453",
note = "A preliminary version appeared as JAIST Technical
Report IS-RR-97-0032F in 1997.")