A search for data was carried out in the databases PubMed, Google Scholar and Hirslan and also by reading through the reference lists of the articles that were found as well as final theses in the database Skemman.
Leitað var að heimildum í gagnasöfnum PubMed, Google Scholar og Hirslunni og með því að skoða heimildaskrár greina sem fundust ásamt lokaverkefnum í Skemmunni.