Package check result: NOTE

Check: CRAN incoming feasibility, Result: NOTE
  Maintainer: ‘David Robelin <david.robelin@inrae.fr>’
  
  Found the following (possibly) invalid URLs:
    URL: https://pmc.ncbi.nlm.nih.gov/articles/PMC53667/
      From: DESCRIPTION
      Status: 403
      Message: Forbidden