Bobryshev, Oleksandr, Stefan A. Buehler, Viju O. John, Manfred Brath, and Helene Brogniez (2018), Is There Really a Closure Gap Between 183.31-GHz Satellite Passive Microwave and In Situ Radiosonde Water Vapor Measurements?, IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, 56(5), 2904-2910, doi:10.1109/TGRS.2017.2786548.