1. Stanford Center for Biomedical Informatics Research, Stanford University, Stanford, CA 94305, USA. E-mails: {noy, musen}@stanford.edu
2. National Cancer Institute, Center for Biomedical Informatics and Information Technology, Bethesda, MD 20892-8335, USA. E-mails: {decoronos, fragosog, hartel}@mail.nih.gov
3. Apelon Inc. Ridgefield, CT, USA. E-mail: hsolbrig@apelon.com