For MMZ9WT, the best reference is probably Rubin & Rubin (2012), because a swapping-events article in your corpus uses them for exactly this point: semi-structured interviews combine “a flexible and open-ended style of questioning” with “a pre-established topic guide,” and allow follow-up/probing questions ZAMYQY.

You could rewrite the sentence like this:

Semi-structured interviews combine a pre-established topic guide with flexible, open-ended questioning, allowing researchers to follow participant accounts and ask follow-up questions while maintaining thematic consistency across the data (Rubin and Rubin 2012).

Bibliography entry:

Rubin, Herbert J., and Irene S. Rubin. 2012. Qualitative Interviewing: The Art of Hearing Data. 3rd ed. Thousand Oaks, CA: Sage.