each work signed on the reverse. signed and described in pencil on the reverse: 'OPALKA 1965 / 1-? | [artist's signature]' and 'Installationsfotos 1A'. signed and described in pencil on the reverse: 'OPALKA 1965 / 1-? | [artist's signature]' and 'Installationsfotos 1B'. signed and described in pencil on the reverse: 'OPAL 1965/1' - ? | [artist's signature]' and 'Installationsfotos 2A'. signed and described in pencil on the reverse: 'OPALKA 1965/1' - ? | [artist's signature]' and 'Installationsfotos 2B'. signed and described in pencil on the reverse: 'OPALKA 1965/1' - ? | [artist's signature]' and 'Installationsfotos'
