The Particle Physics Group (PDG) is an "international collaboration that reviews particle physics and related areas of Astrophysics, and compiles/analyzes data on particle properties." The Web site features the 2002 publication, The Review of Particle Physics, which is described as "the most cited publication in particle physics during the last decade." Visitors have access to summary tables and conservation laws; reviews, tables, and plots; and particle listings, which list, average, evaluate, and reference various data used. Other features include a link to particle physics information and databases, archives of past reports, and other helpful resources.