Essential Web Sites

Scott Lowther wrote:
Earl Colby Pottinger wrote:

Anyway, what do people consider the essential web sites for useful papers are?


http://patft.uspto.gov/netahtml/search-adv.htm
http://ntrs.nasa.gov/
http://library.lanl.gov/catalog/
http://www.llnl.gov/library/catalogs.html


The NACA digital archive can be surprisingly usefull too.
Maybe not quite cutting-edge.