1   6. Optically Variable Close Binary Sources of Strong, Variable X-ray Radiation (X-ray Sources)

1.1  6.1 - X

1.2  6.2 - XB

1.3  6.3 - XF

1.4  6.4 - XI

1.5  6.5 - XJ

1.6  6.6 - XND

1.7  6.7 - XNG

1.8  6.8 - XP

1.9  6.9 - XPR

1.10  6.10 - XPRM - XM