Liu, R.-Y., Yan, H., Wang, X.-Y., Shao, S., & Li, H. (2019). Gamma-Ray Production in the Extended Halo of the Galaxy and Possible Implications for the Origin of Galactic Cosmic Rays. Astrophysical Journal, 871(1), Article 40. https://doi.org/10.3847/1538-4357/aaf567