I think you need to start with such book as (Manipulation and Ideologies in the Twentieth Century: Discourse, Language, Mind), edited by Louis de Saussure and Peter Schulz. I am not sure its level suits undergrads, but it will help you locate other references, among which I hope you find a book that is level appropriate so to speak.
One of the advantages of CDA is that it encourages students reading to move away from focusing on form for its own sake and to use language to explore and provide evidence of the text‟s ideological positioning (Wallace, 1992). In a similar vein, teachers can expand critical writing in a „pre-writing, while-writing, and post-writing‟ procedure in order to encourage students to move away from focusing on form to use language to produce implied meaning.
Teachers can employ CDA instruction to not only enhance learners‟ language awareness but also put a step further to develop their critical language awareness. This can assist students to develop critical minds and, as a result, they not only reach the ability to produce critical texts but can also gain the ability of argumentation to defend their beliefs and ideologies in a democratic life.