Literature sources:

A5: V.P.Goranskij, UBVRI photometry with the 50 cm Maksutov telescope and CCD Apogee Alta U8300 at the SAI Crimean Station.
Ak: V.P.Goranskij with the guide of SAO Zeiss-1000 telescope and Atik 414ex CCD.
ASA: ASASSN.
FR: F. Romanov,CBAT, vsnet-alert 26107.
FW: F.Watanabe (Nayoro Obs.), CBAT.
KS: K.Ikonnikova, K.Sokolovsky, CBAT.
MMA: U.Munari, S.Moretti, A.Maitan, V.Andreoli, ATel#14816, 2021.
SK: S.Kiyota, CBAT.
SO: V.P Goranskij, UBVRI photometry with the SAO 1 m Zeiss and CCD EEV42-40.
ZTF: Zwicky Transient Facility Lasair.