Callahan, R. B. (2014). Private college enrollment in the Midwest: An exploration of significant growth within a 10-year period : submitted to Northcentral University in partial fulfillment of the requirements for the degree of Doctor of Philosophy. ProQuest.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रCallahan, Robert B. Private College Enrollment in the Midwest: An Exploration of Significant Growth Within a 10-year Period : Submitted to Northcentral University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. Ann Arbor, MI: ProQuest, 2014.
एमएलए (8वां संस्करण) प्रशस्ति पत्रCallahan, Robert B. Private College Enrollment in the Midwest: An Exploration of Significant Growth Within a 10-year Period : Submitted to Northcentral University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. ProQuest, 2014.