| PM | history, geography, and the environment b-out d-out ah |
| PNe | history d-out ah |
| PN2 | temporal distribution ah |
| PN2.2 | . cyclical fluctuation ah |
| PN2.2.2 | . . seasonal variation ah |
| PN2.4e | . trend ah |
| PN2.4.2 | . . secular trend ah |
| PN2.6 | . forecast ah |
| PN4 | AOD history ah |
| PN4.2e | . history of AOD use ah |
| PN4.2.2 | . . history of alcohol use ah |
| PN4.4e | . history of AOD prevention ah |
| PN4.6e | . history of AODD treatment ah |
| PN4.8e | . history of AOD public policy ah |
| PN4.8.2e | . . Prohibition Era ah |
| PN4.8.4e | . . post-Prohibition Era ah |
| PN4.10 | . history of AOD production ah |
| PN6 | archaeology ah |
| PQe | historical period d-out ah |
| PQ2 | . ancient history ah |
| PQ4 | . medieval history ah |
| PQ6 | . modern history ah |
| PQ6.4 | . . modern American historical period ah |
| PQ6.4.2 | . . . colonial period (US) ah |
| PQ6.4.4 | . . . Revolutionary War period ah |
| PQ6.4.6 | . . . Civil War period ah |
| PQ6.4.8 | . . . World War I period ah |
| PQ6.4.10 | . . . Great Depression era ah |
| PQ6.4.12 | . . . World War II period ah |
| PQ6.4.14 | . . . Korean War period ah |
| PQ6.4.16 | . . . Vietnam War period ah |
| PQ6.4.18 | . . . Persian Gulf War period ah |
| PQ8 | . historical periods by century/decade ah |
| PQ8.2 | . . pre-5th century ah |
| PQ8.4 | . . 5th-9th century ah |
| PQ8.6 | . . 9th century ah |
| PQ8.8 | . . 10th century ah |
| PQ8.10 | . . 11th century ah |
| PQ8.12 | . . 12th century ah |
| PQ8.14 | . . 13th century ah |
| PQ8.16 | . . 14th century ah |
| PQ8.18 | . . 15th century ah |
| PQ8.20 | . . 16th century ah |
| PQ8.22 | . . 17th century ah |
| PQ8.24 | . . 18th century ah |
| PQ8.24.2 | . . . 1700s ah |
| PQ8.24.4 | . . . 1710s ah |
| PQ8.24.6 | . . . 1720s ah |
| PQ8.24.8 | . . . 1730s ah |
| PQ8.24.10 | . . . 1740s ah |
| PQ8.24.12 | . . . 1750s ah |
| PQ8.24.14 | . . . 1760s ah |
| PQ8.24.16 | . . . 1770s ah |
| PQ8.24.18 | . . . 1780s ah |
| PQ8.24.20 | . . . 1790s ah |
| PQ8.26 | . . 19th century ah |
| PQ8.26.2 | . . . 1800s ah |
| PQ8.26.4 | . . . 1810s ah |
| PQ8.26.6 | . . . 1820s ah |
| PQ8.26.8 | . . . 1830s ah |
| PQ8.26.10 | . . . 1840s ah |
| PQ8.26.12 | . . . 1850s ah |
| PQ8.26.14 | . . . 1860s ah |
| PQ8.26.16 | . . . 1870s ah |
| PQ8.26.18 | . . . 1880s ah |
| PQ8.26.20 | . . . 1890s ah |
| PQ8.28 | . . 20th century ah |
| PQ8.28.2 | . . . 1900s ah |
| PQ8.28.4 | . . . 1910s ah |
| PQ8.28.6 | . . . 1920s ah |
| PQ8.28.8 | . . . 1930s ah |
| PQ8.28.10 | . . . 1940s ah |
| PQ8.28.12 | . . . 1950s ah |
| PQ8.28.14 | . . . 1960s ah |
| PQ8.28.16 | . . . 1970s ah |
| PQ8.28.18 | . . . 1980s ah |
| PQ8.28.20 | . . . 1990s ah |
| PQ8.30 | . . 21st century ah |
| PQ8.30.2 | . . . 2000s ah |
| PQ8.30.4 | . . . 2010s ah |
| PQ8.30.6 | . . . 2020s ah |
| PQ8.30.8 | . . . 2030s ah |
| PT | geography d-out ah |
| PT2 | geographic distribution ah |
| PT4 | physical geography ah |
| PT4.2 | . physical feature of the earth ah |
| PT4.4e | . geographic factors ah |
| PT4.6e | . climate and weather ah |
| PT6 | human geography ah |
| PT6.2 | . land use ah |
| PVe | geographical area d-out ah |
| PV2 | local area ah |
| PV2.2 | . local regional area ah |
| PV2.4e | . urban area ah |
| PV2.4.2 | . . large urban area ah |
| PV2.4.4 | . . small urban area ah |
| PV2.6e | . suburban area ah |
| PV2.8e | . rural area ah |
| PV4 | beyond local area ah |
| PV4.2 | . state wide area ah |
| PV4.4 | . regional area ah |
| PV4.6 | . national area ah |
| PV4.8 | . international area ah |
| PZ | environment d-out ah |
| PZ2 | physical environment ah |
| PZ2.2 | . environmental impact ah |
| PZ2.4 | . environmental pollution ah |
| PZ2.4.2 | . . air pollution ah |
| PZ2.4.4 | . . indoor pollution ah |
| PZ2.4.4.2 | . . . smog ah |
| PZ2.4.6 | . . water pollution ah |
| PZ2.4.16 | . . noise pollution ah |
| PZ4e | psychosocial environment ah |
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