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From the comparison of the SFHs of starburst dwarfs with those of Local Group dwarf irregulars, one can see that in both cases the SF regime is rather continuous (gasping), with two main differences: starburst dwarfs always have the strongest SF episode at recent epochs, while the current SF activity of local irregulars is not necessarily the highest peak. Leo A, with the main SF peak a few Gyr ago (Fig. 4) is quite typical. On the other hand, it is interesting to notice that the SF of the SMC region around the very young cluster NGC 602 (Fig. 3), host of HII regions, shows time distribution and current rate per unit area similar to those (Fig. 7) of starburst dwarfs (once called extragalactic HII regions). The former however involves a small area, corresponding to a tiny fraction of the SMC, while the latter are global behaviours, referring to the whole galaxy.

By comparing with each other the SFHs derived from the CMDs of (few, small) regions of the LG spirals (Fig. 2), one is tempted to speculate over a possible dependence of the SFHs on their morphological type and luminosity class. M31 (SA b I-II) seems to have had very continuous, almost constant SF, since the earliest epochs. The solar neighbourhood of the MW (SAB bc II-III) also shows a rather continuous SF regime, but with larger differences between the rate of the SF peaks and dips, see e.g. Rocha-Pinto & Maciel (1997), Hernandez, Valls-Gabaud & Gilmore (2000) and Cignoni et al. (2006). M33 (SA c III) definitely has significant bumps and gasps over its SFH, with a distribution of SFR with time almost undistinguishable from that derived for the late-type dwarf Leo A. One could then argue that the later the morphological type and the lower the luminosity class of the spirals, the more similar their SFH to those of late-type dwarfs.

Aside from speculations, the general results drawn from all the SFHs derived so far for galaxies with CMDs studies can be summarized as follows:

Acknowledgements The Symposium organizers and IAU are gratefully acknowledged for partial financial support. I thank M. Cignoni and A. Cole for preparing figures ad hoc for this paper, and A. Dolphin and C. Gallart for the SFH plots shown in advance of publication. Some of the results described here have been obtained thanks to frutiful, recurrent and pleasant collaborations with A. Aloisi, L. Angeretti, F. Annibali, M. Cignoni, L. Greggio, A. Nota, and E. Sabbi.

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