The Porosity of the neutral ISM in 20 THINGS Galaxies I. Bagetakos, E. Brinks, F. Walter, W.J.G. de Blok, A. Usero, A.K. Leroy, J.W. Rich and R.C. Kennicutt Jr. EAS Publications Series, 52 (2011) 103-106 Published online: 25 November 2011 DOI: 10.1051/eas/1152015