Jim Seibert's stuff: Some of Jim Seibert's (RIP) writings
NOTE on above items:
Everything is terribly outdated. My real current contact (as of 4-30-2011) is jesseg (at symbol) nikola (dawt symbol) see oh em.
Some of the information on transformers is inaccurate relating to phase shifting.
If you're wishing for the old page here, sorry, I think I deleted it accidentally.