In the contemporary information-rich academic environments, the superabundance of information sources requires that readers compose balanced referential representations of topics presented in sets of sources that provide divergent standpoints on them. Prior beliefs have been reported to skew the representations that readers build based on such sources. In light of the strong link between source reading and integrated writing, the current study examined how reader-writers' prior beliefs affect the propositional content in their integrated written representations (N = 45). Additionally, in light of the necessity to identify conditions that guard against belief biases in the reader-writers' representations, the study examined how strategic source processing affects propositional content in the integrated representations. General Linear Model analyses revealed a biasing effect for pre-existing topical beliefs on the propositional content in L2 reader-writers' integrated representations. The analyses further revealed that accumulation, as a subset of surface-level source reading strategies, exerted a main effect but no moderating effect on the propositional content. On the other hand, cross-text elaboration, as a category of deep-level strategic processing attempts, was shown to moderate the inclusion of pro-belief and contra-belief propositional content in the integrated representations. Implications are provided for integrated writing instruction.