Dinitz, Jeffrey H., and Gregory S. Warrington. “The Spectra of Certain Classes of Room Frames: The Last Cases”. The Electronic Journal of Combinatorics 17, no. 1 (May 20, 2010): R74. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v17i1r74.