Wartiovaara K, Salo M, Sainio K, Rintala R, Sariola H. Distribution of glial cell line-derived neurotrophic factor mRNA in human colon suggests roles for muscularis mucosae in innervation. J Pediatr Surg. 1998 Oct;33(10):1501–6. doi: 10.1016/s0022-3468(98)90485-7. PMID: 9802801.