Tiner, R. 2014. Dichotomous Keys and Mapping Codes for Wetland Landscape Position, Landform, Water Flow Path, and Waterbody Type: Version 3.0. US Fish and Wildlife Service, National Wetlands Inventory Program, Hadley, MA.

https://www.fws.gov/northeast/ecologicalservices/pdf/wetlands/Dichotomous_Keys_and_Mapping_Codes_for_Wetland_Landscape_Position_Landform_Water_Flow_Path_and_Waterbody_Type_Version_3.pdf

This document contains detailed background information on descriptors and keys for wetland mapping. It contains wetland keys, waterbody keys, and information regarding coding systems for LLWW descriptors.