2WGU:
reference: Design, synthesis, and evaluation of N-acyl modified sialic acids as inhibitors of adenoviruses causing epidemic keratoconjunctivitis., Johansson S, Nilsson E, Qian W, Guilligay D, Crepin T, Cusack S, Arnberg N, Elofsson M, J Med Chem. 2009 Jun 25;52(12):3666-78. PMID: 19456100

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