Ow SY, Cardona T, Taton A, Magnuson A, Lindblad P, Stensj? K, Wright PC. Quantitative shotgun proteomics of enriched heterocysts from Nostoc sp. PCC 7120 using 8-plex isobaric peptide tags. J Proteome Res. 2008 Apr; 7(4):1615-28.