Aya Alhussein, Ayman El Zein, The King Degree and the Second Out-Degree of Tournaments, Discrete Math. 348 (2025) 114497.

Ayman El Zein, Non-Hamiltonian Cycles in Tournaments, J. Graph theory.

Ayman El Zein, About kings and dominating sets in tournaments, Austral. J. Combin.