Book titles can be underlined when they are included in an article, or they can be italicized. Both of these options are acceptable, but an author should choose one or the other and be consistent throughout the article.
Sacred book titles, such as the Bible or the Koran, should not be italicized or underlined. Double quotation marks should be used on short works, such as an article from a periodical or a short story. Short works only require quotation marks and should not be italicized or underlined. A title used within the title of an article should be italicized instead of underlined.