Spectral properties of Titan's impact craters imply chemical weathering of its surface. - Neish CD; Barnes JW; Sotin C; MacKenzie S; Soderblom JM; Le Mouélic S; Kirk RL; Stiles BW; Malaska MJ; Le Gall A; Brown RH; Baines KH; et al. (Geophysical research letters, 2015)