WATTS, Robert, YAM POSTCARD, 1962, Printed matter, Museum of Contemporary Art Tokyo, Tokyo. https://dartabase.art/cite/tomuco/6386016

WATTS, Robert, Stamps, 1993, Printed matter, Museum of Contemporary Art Tokyo, Tokyo. https://dartabase.art/cite/tomuco/6386017

WATTS, Robert, Stamps, 1993, Printed matter, Museum of Contemporary Art Tokyo, Tokyo. https://dartabase.art/cite/tomuco/6386018

WATTS, Robert, Stamps, 1993, Printed matter, Museum of Contemporary Art Tokyo, Tokyo. https://dartabase.art/cite/tomuco/6386019

WATTS, Robert, Stamps, 1999, Printed matter, Museum of Contemporary Art Tokyo, Tokyo. https://dartabase.art/cite/tomuco/6386020

WATTS, Robert, Stamps, 1999, Printed matter, Museum of Contemporary Art Tokyo, Tokyo. https://dartabase.art/cite/tomuco/6386021