RT Journal Article SR Electronic T1 CHRISTO'S UMBRELLAS JF Landscape Journal FD University of Wisconsin Press SP 204 OP 207 DO 10.3368/lj.11.2.204 VO 11 IS 2 A1 Dalton, Deborah YR 1992 UL http://lj.uwpress.org/content/11/2/204.abstract AB