- The blocks with four irreducible characters, J. M. Martínez, N. Rizo, L. Sanus 2021. 

In press

- Character degrees in separable groups, G. Navarro, N. Rizo, L. Sanus 2021. 

To appear in Proceedings of the American Mathematical Society.

- Kernels of p'-degree irreducible characters, A. Moretó, N. Rizo, 2021. 

To appear in Mediterranean Journal of Mathematics.

- Nilpotent and perfect groups with the same set of character degrees, G. Navarro, N. Rizo.

J. Algebra Appl. 13 (2014), no. 8,  3 pp.