Chat-based Computer Supported Collaborative Learning (CSCL) often suffers from limitations due to the communication medium. A frequently reported consequence is the lack of discourse coherence and by this a lack of cognitive coherence in the learning process. To overcome these deficiencies, the implementation of explicit references with chat messages caused higher learning results. We analysed eye movements during a chat-based CSCL scenario to gain indications of learners' use of explicit references for text processing.