Sources:

Nak:Y.Nakamura;
Fuk:H.Fukushima;
H:A.Henden;
SO: Our observations;
VM: I.B.Voloshina, N.V.Metlova, in "Physics of cataclysmic variables and related objects", B.T.Gaensicke, K.Bauermann, K.Reinsch. ASP Conf. Ser. V.261, 669, 2002