Photometric and spectral observations of two W UMa stars with periods of one third of a day Kjurkchieva, D. P. ; Marchev, D. V. ; Popov, V. A. Abstract Publication: Astronomische Nachrichten Pub Date: July 2018 DOI: 10.1002/asna.201813483 Bibcode: 2018AN....339..472K