First evidence of multiple populations along the AGB from Strömgren photometry Pieter Gruyters, Luca Casagrande, Antonino P. Milone, Simon T. Hodgkin, Aldo Serenelli and Sofia Feltzing A&A, 603 (2017) A37 Published online: 04 July 2017 DOI: 10.1051/0004-6361/201630341