Deletion of Concept 21

Comment: https://aaa.org.hk/en/collection/search/library/chinas-first-performance-artists-group-concept-21-21 either the first performance art group or https://books.google.com/books?id=mRmppyhh9W0C&dq part of the first wave of performance artists (pp.51-2) in China - meets  notability #3 and #4. https://www.google.com/search?tbm=bks&hl=en&q=%22concept+21%22+china Google books search returns numerous  .... 
Stance: keep
Cited policy: Wikipedia:Notability (WP:ARTIST||WP:RS||WP:BEFORE)