B.G. Basmaji, Rational nonlinear characters of metabelian groups,
Proc. Amer. Math. Soc. 85 (1982) 175--180.
Y.G. Berkovich, Groups of Prime Power Order, Vol. 1, Walter de Gruyter, 2008.
M.R. Darafsheh and H. Sharifi, Frobenius Q-groups,
Arch. Math. 83 (2004) 102--105.
W. Feit and G.M. Seitz, On finite rational groups and related topics,
Illinois J. Math. 33 (1988) 103--131.
The GAP Group, GAP--Groups, Algorithms, and Programming, Version
4.7.4; 2015. http://www.gap-system.org
R. Gow, Groups whose characters are rational-valued,
J. Algebra 40 (1976) 280--299.
P. Heged}us, Structure of solvable rational groups,
Proc. Lond. Math. Soc. 90 (2005) 439--471.
B. Huppert, Endliche Gruppen I, Springer-Verlag, Berlin-New York, 1967.
I.M. Isaacs, Character Theory of Finite Groups, Academic Press, New York-London, 1976.
I.M. Isaacs, Finite Group Theory, American Mathematical Society, Providence, 2008.
I.M. Isaacs and G. Navarro, Sylow 2-subgroups of rational solvable groups,
Math. Z. 272 (2012) 937--945.
D. Kletzing, Structure and representations of Q-groups, Lecture Notes in Math. 1084, Springer-Verlag, 1984.
J.G. Thompson, Composition factors of rational finite groups,
J. Algebra 319 (2008) 558--594.