There is a great number of good Langland pages on the Web. Fortunately, the sites below offer a great variety of links, which makes a more detailed list unnecessary.
Plowman Writings, ed. by James M. Dean. Originally Published in Medieval English Political Writings. Kalamazoo, Michigan: Western Michigan University for TEAMS, 1996. www.ub.rug.nl/camelot/teams/plowint.htm