Andrea Cassa: Dinamiche caotiche e misure invarianti.
Tesi Firenze 1995.

Stefano Marmi/Pierre Moussa/J. Yoccoz: The Brjuno functions and their
regularity properties. Comm. Math. Phys. 186 (1997), 265-293.

11558 Pierre Moussa/Andrea Cassa/Stefano Marmi: Continued fractions and
Brjuno functions. Univ. Firenze, rapporto 1997/26 (1997), 12p.

21213 Manuel Stadlbauer: Metrische Zahlentheorie und dynamische Systeme.
Internet 2006, 63p.

J. Yoccoz: Theoreme de Siegel, polynomes quadratiques, et nombres de Brjuno.
Asterisque 231 (1995), 3-88.