Bis(cyclohexanone) Oxalyldihydrazone/Copper(II) Oxide - A Novel and Efficient Catalytic System for Ullmann-type C-N Coupling in Pure Water - Zhu, Xinhai; Ma, Yan; Su, Li; Song, Huacan; Chen, Gong; Liang, Dacheng; Wan, Yiqian (Synthesis, 2006)