  The Asymptotic Giant Branch (AGB) scenario for the formation of multiple
populations has been quantitatively studied in the course of the latest twenty
years, examining the aspects both of nucleosynthesis and of the dynamics of
formation of new stars in a cooling flow at the center of the first generation
cluster, and of the following N{body evolution. The large complex of these
studies finds many validations in the properties of multiple populations. Here
I shortly summarize recent accomplishments in the study of the evolution of
massive AGBs and super-AGBs including the the explanation of anomalous high
lithium abundances in `extreme' second generation stars in wCen and NGC2808.
