Snyder, C. A., Selegue, J. P., Dosunmu, E., Tice, N. C., & Parkin, S. (2003). C,O-dialkylation of Meldrum's acid: synthesis and reactivity of 1,3,7,7-tetramethyl-4H,10H-6,8,9-trioxa-2-thiabenz f azulen-5-one. The Journal Of Organic Chemistry, 68(19), 7455-9. https://doi.org/10.1021/jo034708i (Original work published 2003)