In a recent article published in this journal, Shanahan, Shanahan, and Misischia investigated the differences in how chemists, historians, and mathematicians read text specific to their disciplines. Unlike the chemists and historians, the pair of mathematicians in this study did not consider sources when reading and evaluating their text. In this response, we contend that most mathematicians regularly do consider sources when reading mathematical arguments and papers. We summarize the results of four empirical studies, which suggest that this is the case. (Contains 2 notes.)