The following notes apply when one or several asterisks appear after the name of an institution.

(*) Universities with two or more central webdomains:

• This is a bad practice that not only penalizes their rank but significantly decrease their visibility in search engines. If one university is going to change its webdomain the older one should be immediately and completely discarded. Our policy is to choose the best ranked domain, even if the selected one is the older or the no longer main webdomain. We do not currently try to merge figures from different domains anymore (Imperial, Manchester, München, Barcelona, Cardiff, Zurich, Strasbourg, Dortmünd, Illinois and Griffith).

(**) We are trying to maintain to a minimum the merging/excluding of domains:

• The 20% of the raw numbers for size and visibility of the University of Helsinki is taken out considering that the City Hall shares the same domain.
• Johns Hopkins University, its School of Medicine and other units with different domains are combined in one unique entry, but its MUSE contents are substracted.
• The portal of journals Redalyc has been excluded from the data of the Universidad Autónoma del Estado de México.
• Data from the very large repository CiteSeerX has been excluded from the calculations related to the Pennsylvania State University and the University of Arkansas Fayetteville.
• The same applies for the database DBLP regarding University of Trier in Germany, Dialnet regarding Universidad de La Rioja (Spain), Compludoc from Universidad Complutense de Madrid and the MUSE project from University of Chicago.
• Webpages from the newspaper “La Jornada” have been excluded from the UNAM figures.
• The Jussieu campus webdomain has been merged to the UPMC and its entry deleted.
• The City College from CUNY is included into the main list even without having independent domain.
• We no longer merge the Caltech domain with the Jet Propulsion Laboratory one (under jpl.nasa.gov), or the different entries corresponding to the Warsaw University (Poland) or the Universidad de la República (Uruguay).

(***) The Top 150 ranked universities according to Google Scholar indicator have been checked for major discrepancies with the other variables. An informed guess has been applied in these cases (0.5).