Denkowski, Z., Migorski, S., Papageorgiou, N. S., Migorski, S., Migorski, S., & Παπαγεωργίου, Ν. Σ. (2003). An introduction to nonlinear analysis: Theory. Boston: Kluwer Academic Publishers.

Denkowski, Zdzisaw, Stanisaw Migorski, Nikolaos Socrates Papageorgiou, Stanis»aw Migorski, Stanislaw Migorski, and Νικόλαος Σ Παπαγεωργίου. An Introduction to Nonlinear Analysis: Theory. Boston: Kluwer Academic Publishers, 2003.

Denkowski, Zdzisaw, et al. An Introduction to Nonlinear Analysis: Theory. Boston: Kluwer Academic Publishers, 2003.