See especially the collection of essays, Passover and Easter: Origin and History to Modern Times, ed. Paul F. Bradshaw and Lawrence A. Hoffman (Notre Dame, IN: Univ. of Notre Dame Press, 1999). Those who read Hebrew will want to consult Shmuel Safrai and Ze’ev Safrai, Haggadah of the Sages: The Passover Haggadah (in Hebrew) (Jerusalem: Carta, 1998).