Many of the papers mentioned are available through open access on the Internet, especially those published in PLoS ONE. If a desired paper is not on the journal publisher's own web site it is sometimes downloadable from the web site of one of the authors, usually within a university department web site. Another useful source of downloadable publications is researchgate.net which requires membership. Failing all else, most authors of papers are pleased to send a PDF copy to people who are interested in their work. Commonly, the corresponding author's email address is on the web page for the article on the journal publisher's web site. Failing that, a contact e-address usually can be found on the web site of the author or of one of the coauthors. These are traceable through the author affiliations given on the web page for the article on the journal publisher's web site. Most of the affiliations are retained in the papers references above.