Sriram Sankaranarayanan Henny B. Sipma Zohar Manna Constructing invariants for hybrid systems. 25-55 2008 32 Formal Methods in System Design 1 http://dx.doi.org/10.1007/s10703-007-0046-1 db/journals/fmsd/fmsd32.html#SankaranarayananSM08