1. V.I. Arnold. Small denominators. I: Mappings of the circumference onto itself. Am. Math. Soc., Transl., II. Ser., 46 (1965), 213–284; translation from Izv. Akad. Nauk SSSR, Ser. Mat., 25 (1961), 21–86.
2. A. Berretti, S. Marmi and D. Sauzin, Limit at resonances of linearizations of some complex analytic dynamical systems. Ergodic Theory Dynam. Systems, 20(4) (2000), 963–990.
3. A. Beurling, The collected works of Arne Beurling. Vol. 1. Complex analysis. Edited by L. Carleson, P. Malliavin, J. Neuberger and J. Wermer. Contemporary Mathematicians. Birkhäuser Boston, Inc., Boston, MA, 1989. xx+475 pp.
4. A.D. Bruno, Analytical form of differential equations. Trans. Moscow Math. Soc., 25 (1971), 131–288 and 26 (1972), 199–239.
5. T. Carleman, Les fonctions quasi analytiques. Leçons professées au Collège de France (Collection de monographies sur la théorie des fonctions). (French) [Quasianalytic functions] Gauthier-Villars, Paris, 1926. 115 p.