Here is a couple of books covering the Nanking Massacre:

The Undaunted Women of Nanking: The Wartime Diaries of Minnie Vautrin and Tsen Shui-fang
by: Hua-ling Hu and Lian-hong Zhang (June 30, 2010)

Eyewitnesses to Massacre: American Missionaries Bear Witness to Japanese Atrocities in Nanjing (An East Gate Book)
by: Kai-Yuan Chang and Zhang Kaiyuan (December 2000)

Purple Mountain: A Story of the Rape of Nanking
by: Shouhua Qi (May 18, 2010)

American Goddess at the Rape of Nanking: The Courage of Minnie Vautrin
by: Hauling Hu and Paul Simon (October 1, 2000)

Inventing Japan: 1853-1964 (Modern Library Chronicles)
by: Ian Buruma (November 9, 2004)