  Let $K$ be a complete ultrametric field of charactersitic zero whose
corresponding residue field $\Bbbk$ is also of charactersitic zero. We give
lower and upper bounds for the size of linearization disks for power series
over $K$ near an indifferent fixed point. These estimates are maximal in the
sense that there exist exemples where these estimates give the exact size of
the corresponding linearization disc. Similar estimates in the remaning cases,
i.e. the cases in which $K$ is either a $p$-adic field or a field of prime
characteristic, were obtained in various papers on the $p$-adic case
(Ben-Menahem:1988,Thiran/EtAL:1989,Pettigrew/Roberts/Vivaldi:2001,Khrennikov:2001)
later generalized in (Lindahl:2009 arXiv:0910.3312), and in (Lindahl:2004
http://iopscience.iop.org/0951-7715/17/3/001/,Lindahl:2010Contemp. Math)
concerning the prime characteristic case.
