Catholic Encyclopedia: Abel, Son of Adam 
Commentary on the first murder victim from the traditional Catholic perspective.
http://www.newadvent.org/cathen/01035c.htmCain and Abel
Biblical biography of the rivalrous siblings.
http://www.execulink.com/~wblank/cainabel.htm
Jewish Encyclopedia: Abel
Comparison of the first shepherd in rabbinic, Hellenistic, and Islamic literature.
http://www.jewishencyclopedia.com/view.jsp?artid=216&letter=A
The Murder of Abel
Paper on the literary sources of the figures of Cain and Abel in the Islamic Qur'an.
http://answering-islam.org/Quran/Sources/cain.html
Bible Prophecy: Abel
Profile of the son of Adam from a joint Lutheran and Catholic bible study project.
http://www.aboutbibleprophecy.com/p143.htm
Jewish Virtual Library: Abel
Brief profile of the second son of Adam, with links to Biblical passages.
http://www.jewishvirtuallibrary.org/jsource/biography/Abel.html
