http://www.allergycentre.com.au/diagnosis/urticaria.html
 http://www.healthanswers.com/database/ami/converted/000845.html
 http://www.pathology.iupui.edu/drhood/urticaria.html
 http://www.hkma.com.hk/std/urticar.htm
 http://www.health-line.com/articles/sp960202.htm
 http://www.users.globalnet.co.uk/~aair/urticaria.htm
 http://www.gsdl.com/NP/services/symptoms/skrsurtc.html
 http://www.nethealthcare.com/_medconsult/Dermatology/Urticaria.htm
 http://www.allergycenters.com/urtic.html
 http://www.allergycentre.com.au/diagnosis/urticariacard.html