Second-Order Necessary Conditions for the Infinite-Horizon Variational Problems. - Joël Blot; Naïla Hayek (Math. Oper. Res., 1996)

Conjugate points in infinite-horizon control problems. - Joël Blot; Naïla Hayek (Autom., 2001)

A Note on Luenberger's Zero-Maximum Principle for Core Allocations. - Jean-Michel Courtault; Bertrand Crettez; Naïla Hayek (IGTR, 2007)

A note on Boiteux' surplus function and dual Pareto efficiency. - Jean-Michel Courtault; Bertrand Crettez; Naïla Hayek (Math. Soc. Sci., 2008)

A Generalization of Mixed Problems with an Application to Multiobjective Optimal Control. - Naïla Hayek (J. Optim. Theory Appl., 2011)

The Competition between Internet Service Qualities from a difference Game Viewpoint. - Joël Blot; Naïla Hayek; Ferhan Pekergin; Nihal Pekergin (IGTR, 2012)

Terrorists' Eradication Versus Perpetual Terror War. - Bertrand Crettez; Naïla Hayek (J. Optim. Theory Appl., 2014)

Optimal growth with investment enhancing labor. - Bertrand Crettez; Naïla Hayek; Lisa Morhaim (Math. Soc. Sci., 2017)

Existence and uniqueness of optimal dynamic pricing and advertising controls without concavity. - Bertrand Crettez; Naïla Hayek; Georges Zaccour (Oper. Res. Lett., 2018)

Growth and Insecure Private Property of Capital. - Bertrand Crettez; Naïla Hayek; Lisa Morhaim (Dyn. Games Appl., 2019)

Existence and characterization of optimal dynamic pricing strategies with reference-price effects. - Bertrand Crettez; Naïla Hayek; Georges Zaccour (Central Eur. J. Oper. Res., 2020)

Do charities spend more on their social programs when they cooperate than when they compete? - Bertrand Crettez; Naïla Hayek; Georges Zaccour (Eur. J. Oper. Res., 2020)

A Dynamic Multi-Objective Duopoly Game with Environmentally Concerned Firms. - Bertrand Crettez; Naïla Hayek (IGTR, 2022)

When is frugality optimal? - Bertrand Crettez; Naïla Hayek; Georges Zaccour (Math. Soc. Sci., 2023)

Existence of equilibrium in a dynamic supply chain game with vertical coordination, horizontal competition, and complementary goods. - Bertrand Crettez; Naïla Hayek; Guiomar Martín-Herrán (Eur. J. Oper. Res., 2025)