Add an in-text citation using MLA format. The citation should go immediately after the cited text.
In 1948, the McDonald brothers introduced a process that would become standard practice in fast food restaurants: "For the first time, the guiding principles of a factory assembly line were applied to a commercial kitchen."
Source: Fast Food Nation, Eric Schlosser, chapter 1, page 20. Published by Houghton Mifflin Company, New York 2001: