Parentheses and brackets are internal punctuation marks used to set off material that is nonrestrictive or to alert the reader to the special functions occuring within (as in mathematical and chemical expressions). "Fences" is a broad term describing parentheses, brackets, and braces used in math typesetting. Follow the generally accepted practices, unless APS style differs.
Use parentheses to indicate supplementary expressions.
Fluids (100 ml) were injected as described in the protocol.
Figure 2 shows a fracture of the left femur (subject 3).
Use closing parentheses only for enumerations.
We made the following assumptions: 1) all mice were fasted overnight; 2)...
Use parentheses to indicate references cited in text.
As mentioned by Johns and Brown (13), the hypoxia increases...
Use square brackets to enclose isotopic prefixes in the names of $$$isotopically labeled compounds.
[3H]inulin
Square brackets can also denote $$$concentration.
[Ca2+]
[Ca2+]i
In APS journals, the order of fences is always { [ ( ) ] } — i.e., parentheses, square brackets, curly braces. Repeat this sequence in long and complex equations, if necessary.
Avoid heavy use of multiple, nested parentheses in text, except when used to list chemicals or results data. When possible, use commas or semicolons to set off parenthetical phrases. When in doubt, query the author.
See the sections on Manufacturer Names and Parenthetical Text for more information about how to present information in parentheses.
When writing braces in text, use the «lbrace» and «rbrace» codes. The brace symbols themselves are reserved for complex coding.
last edited 07/25/03