2O7W:
reference: DNA oligonucleotides with A, T, G or C opposite an abasic site: structure and dynamics., Chen J, Dupradeau FY, Case DA, Turner CJ, Stubbe J, Nucleic Acids Res. 2008 Jan;36(1):253-62. Epub 2007 Nov 19. PMID: 18025040

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