Erdős number

My Erdős number is 3:

I published with Edmund Robertson…
…who published with Ákos Seress…
…who published with Paul Erdős.
A. J. Cain, E. F. Robertson & N. Ruškuc
Subsemigroups of groups: presentations, Malcev presentations, and automatic structures’, Journal of Group Theory 9 (2006), no. 3, pp. 397–426.
DOI10.1515/JGT.2006.027. MR2226621.
P. Brooksbank, H. Qin, E. Robertson & Á. Seress
‘On Dowling geometries of infinite groups’, Journal of Combinatorial Theory, Series A 108 (2004), no. 1, pp. 155–158.
DOI10.1016/j.jcta.2004.06.001. MR2087311.
P. Erdős, Z. Füredi, A. Hajnal, P. Komjáth, V. Rödl & Á. Seress.
‘Coloring graphs with locally few colors’, Discrete Mathematics 59 (1986), no. 1–2, pp. 21–34.
DOI10.1016/0012-365X(86)90065-8. MR837951.