1. Monitoring manual for grassland, shrubland, and savanna ecosystems. Volume 1: quick start;Herrick,2005
2. Monitoring manual for grassland, shrubland, and savanna ecosystems. Volume 2: design, supplementary methods and interpretation;Herrick,2005
3. Interpreting indicators of rangeland health, version 4;Pellant,2005
4. The PLANTS database;USDA, NRCS,2011