Motifs in co-authorship networks and their relation to the impact of scientific publications L. Krumov, C. Fretter, M. Müller-Hannemann, K. Weihe and M.-T. Hütt Eur. Phys. J. B, 84 4 (2011) 535-540 Published online: 01 March 2011 DOI: 10.1140/epjb/e2011-10746-5