The AGB population of NGC 6822: distribution and the C/M ratio from JHK photometryL. F. Sibbons, S. G. Ryan, M.-R. L. Cioni, M. Irwin and R. NapiwotzkiA&A, 540 (2012) A135DOI: https://doi.org/10.1051/0004-6361/201118365