| 6FFR: reference: DNA-RNA Hybrid Quadruplexes Reveal Interactions that Favor RNA Parallel Topologies., Haase L, Dickerhoff J, Weisz K, Chemistry. 2018 Aug 7. doi: 10.1002/chem.201803367. PMID: 30084512 |
This OCA 
Structure page
uses Jmol,
developed by the Jmol Development Team
(documentation).