http://www.ecelab.com/circuit-monostable-opamp.htm

http://iitb.vlab.co.in/userfiles/2/file/op-amp%20based%20monostable_theory.pdf

http://psbrahmachary.files.wordpress.com/2010/10/operational-amplifier-741-as-monostable-multivibrator1.pdf

http://newton.ex.ac.uk/teaching/cdhw/Electronics2/PHY2003-11.pdf

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/schmitt.html

http://pcbheaven.com/wikipages/The_Schmitt_Trigger/

http://www.random-science-tools.com/electronics/inverting-schmitt-trigger-calculator.htm

http://www.zen22142.zen.co.uk/Circuits/Switching/schmitt.htm

http://www.circuitstoday.com/schmitt-trigger-using-op-amp

http://www.indiabix.com/electronics-circuits/schmitt-trigger-with-op-amps/

http://www.ecse.rpi.edu/courses/EI/Schmitt.pdf

http://www.physics.ucdavis.edu/Classes/Physics116/Lab10_rev05.pdf

http://www.random-science-tools.com/electronics/schmitt-trigger-calculator.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/square.html

http://www.diyaudio.com/forums/solid-state/87324-sine-wave-square-triangle-wave-generator-using-transistors-op-amps.html

http://www.circuitstoday.com/sawtooth-wave-generator

http://www.circuitstoday.com/triangular-waveform-using-schmitt-trigger 

http://www.ti.com/lit/an/sboa092a/sboa092a.pdf

http://www.d.umn.edu/~snorr/ece2006s5/Lab6.pdf

http://iitb.vlab.co.in/userfiles/2/file/op-amp%20based%20astable_theory.pdf

http://www.engga.uwo.ca/people/asamani/courses/ece238a/Labs/Lab6.pdf