Surah 5:33 Those who wage war against God and His Messenger and strive to spread corruption in the land should be punished by death, crucifixion, the amputation of an alternate hand and foot or banishment from the land: a disgrace for them in this world, and then a terrible punishment in the Hereafter, 34 unless they repent before you overpower them: in that case bear in mind that God is forgiving and merciful. (The Qur’an, Oxford UP, 2004)
http://www.answering-islam.org/Authors/Arlandson/crucify.htm