Robert Shafer conducts the choir in a concert tribute to 9/11 on its 10th anniversary year. Featured on the program are Haydn's Mass In The Time of War and American composer Joel Puckett's 9/11 tribute This Mourning. TCCW 2011 Young American Artists -- soprano Jennifer Weingartner, mezzo-soprano Alexandra Christoforakis and bass Sean Pflueger -- will be featured as soloists. Puckett will sit for a post-concert conversation with Shafer. This Sunday, Feb. 27, at 7 p.m. The National Presbyterian Church, 4101 Nebraska Ave. NW. Tickets are $15 to $45. Call 301-572-6865 or visit thecitychoirofwashington.org.