The 12C2/12C13C isotopic ratio in comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) P. Rousselot, E. Jehin, J. Manfroid and D. Hutsemékers A&A, 545 (2012) A24 Published online: 31 August 2012 DOI: 10.1051/0004-6361/201219265