Final answer:
The passage likely references the online writing lab at Purdue University as a source, indicated by the citation provided. However, peer-reviewed academic publications could also be significant sources, as these are essential for making claims in academic writing.
Step-by-step explanation:
The passage likely uses multiple sources for the authors' statements, but one significant source could be the online writing lab at Purdue University (Purdue OWL). The Purdue OWL is a reputable resource for writing guidelines and citation styles, commonly used by students and writers for academic papers. The reference list you provided includes a citation from Purdue OWL, suggesting that the authors may have used it as a resource. However, without more information about the content of the passage, it's not possible to determine if the Purdue OWL was the most likely source, though it certainly could have been one of them.
Peer-reviewed academic publications are also probable sources since these are considered the gold standard for research and claims made in scholarly writing. If the passage discusses academic topics, these publications would be a strong contender for the source of information.
While the authors' own knowledge and their local university library could contribute to the information presented in the passage, given that the Purdue OWL is cited, it suggests that at least some of the statements in the passage may be sourced from there. Furthermore, the reference to Purdue OWL for information on quoting, summarizing, and paraphrasing indicates that writing techniques covered in the OWL might have been incorporated into the passage.