Two-particle correlations play a pivotal role in understanding the space-time characteristics of particle emission in Heavy-Ion Collisions (HIC). A relative emission source typically represents these characteristics and can be obtained from transport model simulations such as the Boltzmann-Uehling-Uhlenbeck (BUU) transport model. In this paper, we use the BUU transport model to simulate p-p sources while simultaneously using HIC correlation data to infer them for the same collisions, combining the Koonin-Pratt equation with Richardson-Lucy deblurring. In comparing the sources, we can isolate and provide a simple parametrization for source tails missing from BUU sources. These tails may be attributed to secondary decays that contribute at least one member of the pair in the source. With a tail added, the BUU can reproduce 80 MeV/u Ar + Sc and Ca + Ca measurements. We investigate the angular dependence of Ca + Ca correlations to infer the angle dependence of slow emissions. Our parametrization for the tail may be employed when no deblurring for source inference is pursued.