Web site of ESSA: HistoryArchived 2013-11-01 at the Wayback Machine(in Spanish) [in Spanish initials a plural is often indicated by a double letter, thus "SS" stands for "Suboficiales", plural]
Web site of ESSA: HistoryArchived 2013-11-01 at the Wayback Machine(in Spanish) [in Spanish initials a plural is often indicated by a double letter, thus "SS" stands for "Suboficiales", plural]