|PATS: Acronym for Evaluation indicators|
|Purpose||Is the intent to INFORM or PERSUADE?|
|Authority||Scholar? Journalist? Experienced in the topic? Whatever it is, what does it mean in the context of history? Of a country? Of a time period?|
|Timeliness||Depends on your topic whether currency is important|
|Scope||Do you want something that covers the topic broadly, specifically, or in-depth? (e.g., respectively, encyclopedias, news or scholarly articles, and books)|
NASA. National Aeronautucs and Space Administration.
Physics.org. A guide to authoritative information on the web in Physics.
Science Research: A free, publicly available deep web search engine that uses advanced "federated search technology" to return high quality results by submitting your search query - in real-time - to other well respected search engines then collating, ranking and dropping duplicates of the results.