Vreken P, van Kuilenburg AB, Hamajima N, Meinsma R, van Lenthe H, Gohlich-Ratmann G, Assmann BE, Wevers RA, van Gennip AH (Dec 1999). "cDNA cloning, genomic structure and chromosomal localization of the human BUP-1 gene encoding beta-ureidopropionase". Biochim Biophys Acta. 1447 (2–3): 251–7. doi:10.1016/s0167-4781(99)00182-7. PMID10542323.
Vreken P, van Kuilenburg AB, Hamajima N, Meinsma R, van Lenthe H, Gohlich-Ratmann G, Assmann BE, Wevers RA, van Gennip AH (Dec 1999). "cDNA cloning, genomic structure and chromosomal localization of the human BUP-1 gene encoding beta-ureidopropionase". Biochim Biophys Acta. 1447 (2–3): 251–7. doi:10.1016/s0167-4781(99)00182-7. PMID10542323.