Balakrishnan, A. V. (1976). Applied functional analysis: Revised and enlarged version of the author's introduction to optimization theory in a Hilbert space. Springer-Verlag.

Balakrishnan, A V. Applied Functional Analysis: Revised and Enlarged Version of the Author's Introduction to Optimization Theory in a Hilbert Space. New York: Springer-Verlag, 1976.

Balakrishnan, A V. Applied Functional Analysis: Revised and Enlarged Version of the Author's Introduction to Optimization Theory in a Hilbert Space. Springer-Verlag, 1976.