Xi, J.(2001). Biosynthesis of the thiazole moiety of thiamin in Escherichia coli: Identification of an acyldisulfide-linked protein–protein conjugate that is functionally analogous to the ubiquitin/E1 complex. Proceedings of the National Academy of Sciences, 98(15), 8513-8518. doi:10.1073/pnas.141226698

Xi, Jun. "Biosynthesis of the Thiazole Moiety of Thiamin in Escherichia Coli: Identification of an Acyldisulfide-linked Protein–protein Conjugate That Is Functionally Analogous to the Ubiquitin/E1 Complex". Proceedings of the National Academy of Sciences, 98.15 ( 2001 ): 8513-8518.