Usenko, I. A.; et al. (July 2013), "Spectroscopic studies of southern-hemisphere Cepheids: Six objects in Centaurus (V Cen, V737 Cen) and Sagittarius (BB Sgr, W Sgr, X Sgr, Y Sgr)", Astronomy Letters, 39 (7): 432–445, Bibcode:2013AstL...39..432U, doi:10.1134/S1063773713070074, S2CID121213614.
Usenko, I. A.; et al. (July 2013), "Spectroscopic studies of southern-hemisphere Cepheids: Six objects in Centaurus (V Cen, V737 Cen) and Sagittarius (BB Sgr, W Sgr, X Sgr, Y Sgr)", Astronomy Letters, 39 (7): 432–445, Bibcode:2013AstL...39..432U, doi:10.1134/S1063773713070074, S2CID121213614.
Usenko, I. A.; et al. (July 2013), "Spectroscopic studies of southern-hemisphere Cepheids: Six objects in Centaurus (V Cen, V737 Cen) and Sagittarius (BB Sgr, W Sgr, X Sgr, Y Sgr)", Astronomy Letters, 39 (7): 432–445, Bibcode:2013AstL...39..432U, doi:10.1134/S1063773713070074, S2CID121213614.