Amaia Mauriz-Etxabe and I have just published an article in Spanish. You can reed it here:

https://tienda.revistadepsicoterapia.com/catalog/product/view/id/1600/s/rp116-13/category/3/

The citations for this article is: Erskine, R.G. y Mauriz-Etxabe, A. (2020). Inferencia, Re-experimentación y Regresión: Psicoterapia de los Estados Niño del Yo. Revista de Psicoterapia, 31(116), 205-226. https://doi.org/10.33898/rdp. v31i116.362

The English translation of the title is "Inference, Reexperiencing and Regression: Psychotherapy of Child Self States".