The BL lac phenomenon [electronic resource] : x-ray observations of transition objects ; Determination of the x-ray spectrum of a complete sample of flat -pectrum radio sources / D.M. Worrall ... [et al.]
Imprint
[Greenbelt, Md. : National Aeronautics and Space Administration, Goddard Space Flight Center ; Springfield, Va. : For sale by the National Technical Information Service, 1994]
