Production of two gluons in the Lipatov effective action formalism M. A. Braun, M. Yu. Salykin and M. I. Vyazovsky Eur. Phys. J. C, 65 3-4 (2010) 385-394 Published online: 24 November 2009 DOI: 10.1140/epjc/s10052-009-1184-y