Abstract Expressionism will be well-represented at Christie’s Postwar and Contemporary Art Evening Sale on Tuesday, May 10. In addition to a 1957 canvas by Mark Rothko, the auction will include Clyfford Still’s 1948 work, PH-234. Paintings by Still rarely appear at auction as the majority of his works reside in public institutions. PH-234 is expected to fetch $25-$35 million.