Location of our galaxies in the M_BH-σ relation, compiled by van den Bosch (2016), represented by the gray points and the fitted line, of slope 5.35. Our galaxies are in red, while in blue are plotted other values recently obtained from the CO line: NGC 1097 (Onishi et al. 2015), NGC 1332 (Barth et al. 2016), NGC 3665 (Onishi et al. 2017), NGC 4429 (Davis et al. 2018a), NGC 4526 (Davis et al. 2013), NGC 4697 (Davis et al. 2017). Previous estimations of the BH masses of our sample galaxies are also plotted in green (Table 6), turquoise and pink (Cols. 2 and 3 in Table 7).