According to the Modern Language Association (MLA), the piece of information that must appear within parentheses in an in-text citation of a book source if it does not appear in the sentence itself is: The author's surname and the page number from where the information was taken.
According to the Modern Language Association citation style, the author's name and the page number from where the information was extracted should be included in parentheses. There are different citation styles and this is the requirement for the MLA style.
The author's surname is very important because it will show that the direct words being quoted are not the words of the writer but those of another person. The page number from which the information was extracted must also be included. This is important because it will help the reader who wants to make further inquiries to easily locate the source of the quote.
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