Marcelo F. Frias Gabriel Baum T. S. E. Maibaum Interpretability of First-Order Dynamic Logic in a Relational Calculus. 66-80 2001 conf/RelMiCS/2001 RelMiCS http://link.springer.de/link/service/series/0558/bibs/2561/25610066.htm db/conf/RelMiCS/RelMiCS2001.html#FriasBM01