Galaxy Zoo: Dust lane early-type galaxies are tracers of recent, gas-rich minor mergers - Shabala, S; Ting, Y; Kaviraj, S; Lintott, C; Crockett, R; Silk, J; Sarzi, M; Schawinski, K; Bamford, S; Edmondson, E (Monthly Notices of the Royal Astronomical Society, 2012)