Spellberg MA (January 1959). "Hexylcaine (cyclaine) as topical anesthetic in gastroscopy and esophagoscopy". Gastroenterology. 36 (1): 120–1. doi:10.1016/S0016-5085(59)80102-5. PMID13620024.
nih.gov
pubmed.ncbi.nlm.nih.gov
Spellberg MA (January 1959). "Hexylcaine (cyclaine) as topical anesthetic in gastroscopy and esophagoscopy". Gastroenterology. 36 (1): 120–1. doi:10.1016/S0016-5085(59)80102-5. PMID13620024.