If you use PyRVLIN, please cite the original paper.
RVLIN is a set of routines that quickly fits an arbitrary number of Keplerian curves to radial velocity data. It can handle data from multiple telescope (i.e. it solves for the offset), constraints on P, e, and time of peri passage, and now can incorporate transit timing data. To use transit information, fix the transit time of planets using the tts= keyword. For multiplanet systems, the length n vector passed to tts will contain the fixed transit time of the first n planets in the system.