Even though called “Diego“, until 1965 he signed his works of art some form of “Voci“. See signature gallery below and on Antonio Diego Voci Wikipedia:
From 1962 thru 1965 Diego was represented at the prestigious Schlossgalerie (see below) and an image of a 1965 ad from a Zurich newspaper. He began signing “Diego” in 1966.
diegovociproject 