6QCS:
reference: Structural snapshots of actively transcribing influenza polymerase., Kouba T, Drncova P, Cusack S, Nat Struct Mol Biol. 2019 Jun;26(6):460-470. doi: 10.1038/s41594-019-0232-z. Epub, 2019 Jun 3. PMID: 31160782

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