Whigham, Dennis F., Lee, Lyndon C., Brinson, Mark M., Rheinhardt, Richard D., Rains, Mark C., Mason, Jeffrey A., Kahn, Humaira, Ruhlman, Melanie B., and Nutter, Wade L. 1999. "
Hydrogeomorphic (HGM) assessment - a test of user consistency."
Wetlands. 19 (3):560–569.