COMPARISON OF RADIATION MEASUREMENTS BY BTN AND R3DR INSTRUMENTS OUTSIDE INTERNATIONAL SPACE STATION. - Dachev, Tsvetan; Semkova, Jordanka; Tomov, Borislav; Matviichuk, Yury; Dimitrov, Plamen; Bankov, Nikolay; Koleva, Rositza; Jordanova, Malina; Litvak, Maxim; Mitrofanov, Igor; Golovin, Dmitry; Kozyrev, Alexander; et al. (Aerospace Research in Bulgaria, 2020)