On quasi-periodic intrinsic light varability in a close spectroscopic binary CX DraPustõlnik, Izold; Kalv, Peep; Harvig, Voldemar; Aas, ToomasModern problems of astronomy2007 / p. 54 https://www.researchgate.net/publication/241210511_On_Quasi-Periodic_Intrinsic_Light_Variability_in_a_Close_Spectroscopic_Binary_CX_DRA

The Tallinn Public Observatory in changing conditionsMars, Mario; Aas, Toomas; Harvig, VoldemarModern problems of astronomy2007 / p. 50