Package check result: NOTE

Check: CRAN incoming feasibility, Result: NOTE
  Maintainer: ‘Jing Hua Zhao <jinghuazhao@hotmail.com>’
  
  Found the following (possibly) invalid URLs:
    URL: https://www.amazon.com/dp/0126913609/
      From: man/b2r.Rd
      Status: 500
      Message: Internal Server Error
    URL: https://www.amazon.com/dp/0470689285/
      From: man/muvar.Rd
      Status: 500
      Message: Internal Server Error
    URL: https://www.amazon.com/dp/7111109457/
      From: man/b2r.Rd
            man/qqunif.Rd
      Status: 500
      Message: Internal Server Error
    URL: https://www.amazon.com/dp/B011SJAWXG/
      From: man/qqunif.Rd
      Status: 500
      Message: Internal Server Error
    URL: https://www.amazon.com/dp/B01A0BLZKM/
      From: man/qqfun.Rd
            man/qqunif.Rd
      Status: 500
      Message: Internal Server Error

No changes to worse in reverse depends.