中國抗戰史的研究, 費正清說

"During eight years of war, a major part of the Chinese people were in Japanese-occupied territory, mainly the coastal cities and railway towns. Another major segment were in the GMD-controlled area, called Free China. The smallest division of China was the CCP area, with its capital at Yan'an. Historians are genetic-minded, looking for origins, and China's future came out of Yan'an. Accordingly, the defeat of the Japanese and of the Nationalists has been less researched than the rise of the CCP. Success is creative and interesting; failure is sad and dull. Who wants it? Moreover, Yan'an being smaller, in size and documentation, is easier to encompass than the vastly variegated experience of occupied China and Free China. These two areas, though larger than the area under Yan'an, have been less studied."

節錄自 --china's war of resistance-- 大字第二版 費正清著, 第十六章1937-1945, 312 頁.