Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:The two
 baselines considered in our experiments are two representatives from parametric and non-parametric categories: 1) OU (Orstein-Uhlenbeck (Huang et al., 2016)): modeling the drift term using an Orstein-Uhlenbeck process (Gillespie, 1996), which is a stationary Gauss-Markov process with the‚Ä¶
Category: