De Cia, A., Ledoux, C., Savaglio, S., Schady, P., & Vreeswijk, P. M. (2013). Dust-to-metal ratios in damped Lyman-α absorbers - fresh clues to the origins of dust and optical extinction towards γ-ray bursts. Astronomy & Astrophysics, 560: A88, pp. 1-14. doi:10.1051/0004-6361/201321834.