NED object is 3C 028; Reference is 1983MNRAS.203..147M

   Figure 1. The distribution of spectral index {alpha}(5.0, 2.7) for 3C 28.
 Values are given where I_5.0_ > 4 mJy, except for those in brackets. The
 spectral indices are plotted on a grid of 3.0 X 6.8 arcsec**(2), so that
 neighbouring points are independent. They are superposed on a 2.7-GHz map of
 I-Q, which has a contour interval of 4 mJy and the zero contour omitted.