this low-distortion crystal oscillator is essentially a modified Clapp oscillator that uses a four-transistor voltage follower instead of a single transistor and connects the crystal to a virtual ground
http://www.edn.com/archives/1994/081894/17di1.htm
drive heavy loads, the duty cycle is adjustable from 25 to 75%; and feedback minimizes the drift
http://www.edn.com/archives/1998/081798/17di.htm
The oscillator starts with a readily available 96MHz crystal and multiplying this by 25 goes up to 2400MHz. The use of filters takes the guesswork out of finding the correct frequencies. The output is -10dBm
http://www.qsl.net/g3pho/13cm.htm
continuously operating 32KHz crystal oscillator to the input of a C-MOS buffer when clock pulses are needed, standby power consumption to a very low 1uA when used with a 3v supply.
http://www.imagineeringezine.com/PDF-FILES/gatextl.pdf