Notes. The fits to radial velocity data for HD 82943 (2:1 resonance) and HD 45364 (3:2 resonance) were taken from Fit II of (Lee et al. 2006), although the planetary masses correspond to Fit I, and (Correia et al. 2009) respectively. It is implicitly assumed that the system is coplanar and the minimum masses derived from the data are representative of the real planetary masses. Although it is understood that different but equally permissible fits to the data can be found, here we retain the quoted values, as we only wish to use the systems as illustrative examples. Moreover, we note that (at least in the case of HD 82943) the quoted elements are represented in Jacobi coordinates, although in practice, their interpretation as Poincar coordinates only introduces negligible errors.