standard deviation of daily return

This paper take "The News Digest" as a case to research, because it has not been studied detailed in academic.

本文以《每日译报》为个案来研究“孤岛”时期的抗日宣传,是因为目前学术界对“孤岛”时期报刊的抗日宣传问题的研究还不够细化。