1. http://www.surgeryencyclopedia.com/Pa-St/Photocoagulation-Therapy.html
2. http://www.retinopathy.org
3. http://diabetes.webmd.com/laser-photocoagulation-for-diabetic-retinopathy
4. http://www.emedicine.com/emerg/topic504.htm
5. http://www.apagrafix.com/patiented/yaglaser/yaglaser.HTM