Bryman, A. (2007). Barriers to integrating quantitative and qualitative research.

This article discusses obstacles to integrating the two approaches, which are still relevant and which you should be familiar with.

Bryman, A. (2007). Barriers to integrating quantitative and qualitative research. Journal of Mixed Methods Research, 1(1), 8–22.

Flick, U., Garms-Homolová, V., Herrmann, W. J., Kuck, J. and Röhnsch, G. (2012). ‘I can’t prescribe something just because someone asks for it …’: Using mixed methods in the framework of triangulation.

In this article, the concept of triangulation is developed as a framework for mixed methods research in the context of a concrete example.

Flick, U., Garms-Homolová, V., Herrmann, W. J., Kuck, J., & Röhnsch, G. (2012). ‘I can’t prescribe something just because someone asks for it …’: Using mixed methods in the framework of triangulation. Journal of Mixed Methods Research, 6(2), 97–110.