Measuring the magnetic field of a trans-equatorial loop system using coronal seismology (Corrigendum)D. M. Long, G. Valori, D. Pérez–Suárez, R. J. Morton and A. M. VásquezA&A, 607 (2017) C3DOI: https://doi.org/10.1051/0004-6361/201730413e