Effects of relative phase in an open ladder system without incoherent pumping X. J. Fan, A. Y. Li, S. F. Tian, D. M. Tong, S. Q. Gong and Z. Z. Xu Eur. Phys. J. D, 42 3 (2007) 483-488 Published online: 23 February 2007 DOI: 10.1140/epjd/e2007-00040-x