Deep Optical Emission-line Images of Nine Known and Three New Galactic Supernova Remnants oleh Robert A. Fesen, Marcel Drechsler, Xavier Strottner, Bray Falls, Yann Sainty, Nicolas Martino, Richard Galli, Mathew Ludgate, Markus Blauensteiner, Wolfgang Reich, Sean Walker, Dennis di Cicco, David Mittelman, Curtis Morgan, Aziz Ettahar Kaeouach, Justin Rupert, Zouhair Benkhaldoun