Citation:
Dupree A K, Davis R J, Gursky H, Hartmann L W, Raymond J C, Boggess A, Holm A, Kondo Y, Wu C-C, Macchetto F, et al. IUE observations of X-ray sources : HD 153919 (4U 1700-37), HDE 226868(Cyg X-1), HZ HER (Her X-1). \nat. 1978;275 :400-403.