Determination of the complex refractive index of cell cultures by reflectance spectrometry Mihaela Antonina Calin, Marian Romeo Calin and Constantin Munteanu Eur. Phys. J. Plus, 129 6 (2014) 116 Published online: 12 June 2014 DOI: 10.1140/epjp/i2014-14116-1