http://www.falstad.com/circuit/e-multivib-bi.html

http://www.play-hookey.com/digital/experiments/rtl_bistable.html

http://www.electronics-tutorials.ws/waveforms/bistable.html

http://electriciantraining.tpub.com/14181/css/14181_117.htm

http://webpages.charter.net/dawill/tmoranwms/Elec_Flipflop.html

http://www.bowdenshobbycircuits.info/page9.htm

http://pcbheaven.com/wikipages/Transistor_Circuits/

http://www.hobbyprojects.com/flip_flop/a_transistor_RS_flip_Flop.html