Standing on the shoulders of giants - Trojan Earths and vortex trapping in low mass self-gravitating protoplanetary disks of gas and solidsW. Lyra, A. Johansen, H. Klahr and N. PiskunovA&A, 493 3 (2009) 1125-1139DOI: https://doi.org/10.1051/0004-6361:200810797