"Designing for South Dakota and the Upper Midwest: The Career of Architect Harold T. Spitznagel, 1930-1974"
https://www.sdhspress.com/journal/south-dakota-history-37-4/designing-for-south-dakota-and-the-upper-midwest-the-career-of-architect-harold-t-spitznagel-1930-1974
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"Designing for South Dakota and the Upper Midwest: The Career of Architect Harold T. Spitznagel, 1930-1974"