Package check result: NOTE

Check: CRAN incoming feasibility, Result: NOTE
  Maintainer: ‘Vikram B. Baliga <vbaliga87@gmail.com>’
  
  Found the following (possibly) invalid URLs:
    URL: https://www.karger.com/Article/Abstract/314284
      From: inst/doc/visual-perception-functions.html
      Status: 403
      Message: Forbidden

No changes to worse in reverse depends.