Juan Perón
Children typically use their fathers' last names only. Some state offices have started to use both last names, in the traditional father then mother order, to reduce the risk of a person being mistaken for others using the same name combinations, e.g. if Eva Duarte and Juan Perón had a child named Juan, he might be misidentified if he were called "Juan Perón", but not if he was known as Juan Perón Duarte.