ABBREVIATIONS, SIGNS, AND SYMBOLS - USGS
pubs.usgs.gov › unnumbered › 7000088abbreviations as "fig.," "pl.," "p.," and "no.," and other nonbibliographic abbreviations such as "a.m.," 6 6 p.m.," "A.D.," and "B.C."). Uncommon abbreviations must be defined the first time they are used in the main text. The standard Survey format is to enclose the abbreviated form in parentheses immediately following the spelled out