In this paper we consider sentences that contain Multiple In-text References (MIR) and their position in the rhetorical structure of articles. We carry out the analysis of MIR in a large scale dataset of about 80,000 research articles published by the Public Library of Science in 7 journals. We analyze two major characteristics of MIR: their positions in the IMRaD structure of articles, and the number of in-text references that make up a MIR in the different journals. We show that MIR are rather frequent in all sections of the rhetorical structure. In the Introduction section, sentences containing MIR account for more than half of the sentences with references.