1. Rockafellar, R.T.: Convex Analysis. Princeton University Press, Princeton (1970)
2. Bertsekas, D.P., Nedić, A., Ozdaglar, A.E.: Convex Analysis and Optimization. Athena Scientific, Belmont (2003)
3. Rockafellar, R.T.: Network Flows and Monotropic Optimization. Wiley, New York (1984). Republished by Athena Scientific, Belmont (1998)
4. Bertsekas, D.P., Mitter, S.K.: Steepest descent for optimization problems with nondifferentiable cost functionals. In: Proc. 5th Annual Princeton Confer. Inform. Sci. Systems, Princeton, NJ, pp. 347–351 (1971)
5. Bertsekas, D.P., Mitter, S.K.: A descent numerical method for optimization problems with nondifferentiable cost functionals. SIAM J. Control 11, 637–652 (1973)