The methodology used in cvscores() is an extension of that described in Maindonald and Burden (2005)

Maindonald J, Burden C (2005). “Selection bias in plots of microarray or other data that have been sampled from a high-dimensional space.” In May R, Roberts A (eds.), Proceedings of 12th Computational Techniques and Applications Conference CTAC-2004, volume 46, C59–C74. https://journal.austms.org.au/V46/CTAC2004/Main/home.html.

Corresponding BibTeX entry:

  @InProceedings{,
    title = {Selection bias in plots of microarray or other data that
      have been sampled from a high-dimensional space},
    journal = {Australian {&} New Zealand Industrial and Applied
      Mathematics Journal},
    volume = {46},
    pages = {C59--C74},
    year = {2005},
    booktitle = {Proceedings of 12th Computational Techniques and
      Applications Conference CTAC-2004},
    editor = {Rob May and A.J. Roberts},
    author = {J.H. Maindonald and C.J. Burden},
    url = {https://journal.austms.org.au/V46/CTAC2004/Main/home.html},
  }