Theory of Oscillator Design, by Erich Hafner
Proc. 17th Annu. Freq. Contr. Symp., May 1963, pp. 508-536.
http://ieee-uffc.org/freqcontrol/tutorials/s6310508.pdfThis paper is the best explanation of oscillators I have yet seen. Hafner shows how to keep the calculations simple and understandable but still exact even when the transistor is not ideal. His quantitative graphical solution is still useful today for qualitative understanding even if you now do the calculations with a SPICE program
IEEE UFFC posted the Hafner paper and lots of other important tutorials and review papers in the free portion of their web site:
http://ieee-uffc.org/fcmain.asp?view=review#tutor
They deserve our thanks and support!
Jiri Vackar, LC Oscillators and their Frequency Stability- the original 1949 paper, complete PDF 4,475KB
This paper is often cited, but very difficult to actually find. It is still useful after almost sixty years.
The only copy a good reference librarian was able to find was at the Naval Postgraduate School in Monterey, CA and it was a poor photocopy. I found an internet reference to a Jiri Vackar in Prague and sent him an email. He turned out to be the son of the author. His father no longer had a copy, but the son found one in the Prague library, scanned it and touched up some faded areas with help from his father and sent this file to me.