|Sorted by Disciplines and Subdisciplines|
|Sorted by Subdisciplines and Disciplines|
|Sorted by Content Categories, Disciplines, and Subdiscipline|

Disciplines, sub-disciplines, and sources are self-explanatory. Most websites have several kinds of information, but it seems useful to classify them according to the dominant category of information content. Our current definitions of the information content categories is as follows:

Association -- Professional society for a discipline or subdiscipline
Catalogue -- Same as directory, but for books not available online
Data -- Credible and relevant numerical data, either raw or statistical
Directory -- Many links (or key links) to other websites with relevant information content
Experts -- Contact information for many subject matter experts (or key experts)
Foundation -- Non-profit research and/or grant-making institution
Journal -- Open access online journals (trade or research)
Knowledge -- The information content is integrated to provide insight and understanding
News -- News services that can be monitored, preferably via email alerts
Research -- Reports of current research activities in relevant disciplines
School -- Educational center of excellence for a discipline or subdiscipline
Standard -- Document that defines quality/other requirements for industrial activity
Text -- The information content is credible but has not been integrated to provide insight and understanding
Trends -- Credible and relevant numerical data, either raw or statistical, amenable to plotting as a time series
Tutorial -- Introduction or overview to a discipline or subdiscipline.