Retinol Hexadecanoate-d31; Retinol Palmitate-d31; 250S/N-d31; 250S/N-B-d31; Aquapalm-d31; Aquasol A-d31; Arovit-d31; Axerophthol Palmitate-d31; Dispatabs Tabs-d31; Lutavit A 500 Plus-d31; Myvak-d31; Myvax-d31; Optovit A-d31; Palmitic Acid Ester with Retinol-d31; Retinyl Palmitate-d31; Testavol S-d31; VAP 250CK-CWD-d31; VAP 250MS-CWD-d31; Vitamin A Palmitate-d31; Vitazyme A-d31; all-trans-Retinol Palmitate-d31; all-trans-Vitamin A Palmitate-d31; trans-Retinol Palmitate-d31; trans-Retinyl Palmitate-d31,Retinyl Palmitate Stable Isotopes