Thomas A. Henzinger
Masaccio is a formal model for hybrid dynamical systems which are built from atomic discrete components (difference equations) and atomic continuous components (differential equations) by parallel and serial composition, arbitrarily nested. Each system component consists of an interface, which determines the possible ways of using the component, and a set of executions, which define the possible behaviors of the component in real time.
Proceedings of the First IFIP International Conference on Theoretical Computer Science (TCS), Lecture Notes in Computer Science 1872, Springer, 2000, pp. 549-563.