Ghosh, A., Gelbwaser-Klimovsky, D., Niedenzu, W., Lvovsky, A. I., Mazets, I., Scully, M. O., & Kurizki, G. (2018). Two-level masers as heat-to-work converters. Proceedings of the National Academy of Sciences, 115(40), 9941–9944. https://doi.org/10.1073/pnas.1805354115