Because of an old rule (plurals get double letter), I believe the recommended way by the Academy is «E.E. U.U.». Not sure if they’ve said otherwise recently.
It’s also not uncommon to see «E.U.A.», «E.U.» or those same but without the dots.
No confusion with the European Union, though, because that’s «Unión Europa»: «U.E.».
Because of an old rule (plurals get double letter), I believe the recommended way by the Academy is «E.E. U.U.». Not sure if they’ve said otherwise recently.
It’s also not uncommon to see «E.U.A.», «E.U.» or those same but without the dots.
No confusion with the European Union, though, because that’s «Unión Europa»: «U.E.».