<A HREF="http://link.springer.com/chapter/10.1007/978-1-4612-5651-9_2">Control theory and singular Riemannian geometry</A> (1982)

<A HREF="http://link.springer.com/article/10.1023%2FA%3A1021684407650?LI=true#page-1">The Condition of Hydrostatic Equilibrium of Stellar Models Using Optimal Control</A> (2002)

<A HREF="http://arxiv.org/abs/1103.0548">Investigating a model of optimized active galactic nucleus feedback</A> (2011)