Nitrogen and hydrogen fractionation in high-mass star-forming cores from observations of HCN and HNCL. Colzi, F. Fontani, P. Caselli, C. Ceccarelli, P. Hily-Blant and L. BizzocchiA&A, 609 (2018) A129DOI: https://doi.org/10.1051/0004-6361/201730576