Both this letter from St. John Bosco to his priests and this article discussing it were recently discussed on a parenting list I belong to.
Both address anger in relationship to correcting children, and how anger poisons the relationship. In the original letter St. John Bosco is addressing priests who were teaching or leading the boys in their care; the article by Dr. John Crosby discusses Bosco's call to forsake anger in the context of parenting, and especially the parental ego.
I think I need to add this saint to the list of those whose intercession I seek daily. Hourly!