Disentangling 2:1 resonant radial velocity orbits from eccentric ones and a case study for HD 27894Martin Kürster, Trifon Trifonov, Sabine Reffert, Nadiia M. Kostogryz and Florian RodlerA&A, 577 (2015) A103DOI: https://doi.org/10.1051/0004-6361/201525872