Package check result: NOTE

Check: CRAN incoming feasibility, Result: NOTE
  Maintainer: ‘Paul R. Hibbing <paulhibbing@gmail.com>’
  
  Found the following (possibly) invalid URLs:
    URL: https://doi-org.proxy.cc.uic.edu/10.1016/j.csda.2006.12.016
      From: inst/doc/tpm.html
      Status: Error
      Message: SSL peer certificate or SSH remote key was not OK [doi-org.proxy.cc.uic.edu]:
        SSL certificate verification failed: certificate signer not trusted. (CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none)

No changes to worse in reverse depends.