journal: Vitamin A: https://en.wikipedia.org/wiki/Vitamin_A CAS number: https://en.wikipedia.org/wiki/CAS_Registry_Number WHO ATC code: https://www.whocc.no/atc_ddd_index/?code=A11CA01 Pub Chem: https://pubchem.ncbi.nlm.nih.gov/compound/1071 Image: https://chemapps.stolaf.edu/jmol/jmol.php?model=OC%2FC%3DC%28C%29%2FC%3DC%2FC%3DC%28C%29%2FC%3DC%2FC1%3DC%28C%29%2FCCCC1%28C%29C