1CDA:
reference: A 3-D model for the CD40 ligand predicts that it is a compact trimer similar to the tumor necrosis factors., Peitsch MC, Jongeneel CV, Int Immunol 1993 Feb;5(2):233-8. PMID: 8095800

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