NED object is MESSIER 033; Reference is 1987A&AS...68..171B

   FIGURE 5.-Distribution of the total intensity at 11.1 cm in the field of M33
 presented as contours in equal steps of 7 mJy per b.a. (2.3 {sigma}).
 Positions of 21 point sources are marked. The coordinate grid is the same in
 all maps and refers to right ascension and declination of 1950.0. The optical
 centre at {alpha}_50_ = 1h31m01.67s and {delta}_50_ = 30deg24'15.0" (de
 Vaucouleurs and Leach, 1981) is marked by << + >> in all figures.