9DNA:
reference: Crystal structure analysis of an A-DNA fragment at 1.8 A resolution: d(GCCCGGGC)., Heinemann U, Lauble H, Frank R, Blocker H, Nucleic Acids Res 1987 Nov 25;15(22):9531-50. PMID: 3684603

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