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2. W. Arriagada, Characterization of the unfolding of a weak focus and modulus of analytic classification, PhD thesis, Université de Montréal, Montréal, Canada, 2010.
3. Finitely generated groups of germs of one-dimensional conformal mappings and invariants for complex singular points of analytic foliations of the complex plane;Elizarov,1993
4. In the theory of normal forms of analytic differential equations, divergence is the rule and convergence the exception when the Bryuno conditions are violated;Ilʼyashenko;Moscow Univ. Math. Bull.,1981
5. Nonlinear Stokes Phenomena;Ilʼyashenko,1993