Giant molecular filaments in the Milky Way - II. The fourth Galactic quadrant J. Abreu-Vicente, S. Ragan, J. Kainulainen, Th. Henning, H. Beuther and K. Johnston A&A, 590 (2016) A131 Published online: 30 May 2016 DOI: 10.1051/0004-6361/201527674