[en] In the study complex reactions, the simple space-time interpretation of pion interferometry often breaks down due to strong correlations between spatial and momentum coordinates. In those cases, pion interferometry is still useful as a complementary test of specific dynamic models, but a refined formalism must be used, as discussed in the introduction. With this formalism, we show that recent NA35 data on O + Au → π^-π^- + X at 200 AGeV are consistent with both hadronic resonance and quark-gluon plasma models for this reaction. The sensitivity of the outward and sideward transverse projected correlation function for pions is investigated. Finally, we compare pion and kaon interferometry predictions of these two models. 31 refs., 3 figs