4IDL:
reference: Structure of a low-melting-temperature anti-cholera toxin: llama V(H)H domain., Legler PM, Zabetakis D, Anderson GP, Lam A, Hol WG, Goldman ER, Acta Crystallogr Sect F Struct Biol Cryst Commun. 2013 Feb 1;69(Pt 2):90-3. doi: , 10.1107/S1744309112050750. Epub 2013 Jan 26. PMID: 23385744

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).