Sergio (?) de Castro abstract painting under glass, 1964

Sergio (?) de Castro abstract painting under glass, 1964.------------------------------Davids notes: Probably some other Castro other than Sergio but we could not, at this late date, determine the artist. Sergio is possible but a stretch. He rarely signed his name like the way it was signed in lot 36.
Condition Report: There is the beginning of spider web type glass cracking in one corner, the previous owner put glue in to stop the glass breakage from spreading.We suggest taking it to a framer for correcting.