The following are courtesy of DR-ED posting from July 9, 2022:

Martin, F., Polly, D., and Ritzhaupt, A. (2020). Bichronous online learning: Blending asynchronous and synchronous online learning.

Martin, F. (2021) Bichronous Online learning: Is blending asynchronous & synchronous the best approach? [Blog post] https://interactions.aect.org/bichronous-online-learning-is-blending-asynchronous-and-synchronous-the-best-approach/

Graham, C. R. (2019). Current research in blended learning. In M. G. Moore & W. C. Diehl (Eds.), Handbook of distance education (4th ed., pp. 173–188). Routledge. 

Joosten, T., Weber, N., Baker, M., Schletzbaum, A., & McGuire, A. (2021). Planning for a blended future: A research-driven guide for educators. [Report] Every Learner Everywhere Network. https://www.everylearnereverywhere.org/resources/ 

Halverson, L. R., & Graham, C. R. (2019). Learner engagement in blended learning environments: A conceptual framework. Online Learning, 23(2), 145- 178. https://doi.org/10.24059/olj.v23i2.1481

Beatty, B. J. (2019). Acknowledgements. In B. J. Beatty (Ed.), Hybrid-Flexible course design. EdTech Books. https://edtechbooks.org/hyflex/Acknowledge

Kelly, K. (2020, May 7). COVID-19 planning for Fall 2020: A closer look at HybridFlexible course design. Phil on Ed Tech. https://philonedtech.com/covid-19-planning-for-fall2020-a-closer-look-at-hybrid-flexible-course-design/ 

Lederman, D. (2020, May 13). The HyFlex option for instruction if campuses open this fall. Inside Higher Ed. https://www.insidehighered.com/digital-learning/article/2020/05/13/one-option-deliveringinstruction-if-campuses-open-fall-hyflex