Carrillo S. A., Hurtado C. A. Gevrey series solutions in analytic functions of first order holomorphic PDEs.  To appear  in the volume "Formal and Analytic Solutions of Differential Equations : Proceedings of the conference FASNET''. World Scientific Publishing Europe Ltd, 2021. [2002.04404] Formal $P$-Gevrey series solutions of first order holomorphic PDEs (arxiv.org)