Jewish Virtual Library: Issachar - Brief profile of the priest, with links to pertinent Torah passages. - http://www.jewishvirtuallibrary.org/jsource/biography/issachar.html
Jewish Encyclopedia: Issachar - Overview of the ninth son of Jacob from the traditional Jewish perspective, including rabbinic commentary. - http://www.jewishencyclopedia.com/view.jsp?artid=360&letter=I
Catholic Encyclopedia: Issachar - Commentary on the son of Jacob from the traditional Catholic perspective. - http://www.newadvent.org/cathen/08201a.htm
Issachar - Biblical biography of the son of Jacob. - http://www.execulink.com/~wblank/20001015.htm
Tsaddikim: Issachar - Presenting the Chassidic position on the son of Jacob, including beliefs about his later reincarnations. - http://judaicaplus.com/Tzadikim/issachar.htm