A rational group is a finite group whose irreducible complex characters are rational valued. The aim of this paper is to classify rational groups $G$ for which every nonlinear irreducible character vanishes only on involutions.
JAFARI, SAEED and SHARIFI, HESAM
"Characterizing rational groups whose irreducible characters vanish only on involutions,"
Turkish Journal of Mathematics: Vol. 39:
3, Article 9.
Available at: https://journals.tubitak.gov.tr/math/vol39/iss3/9