A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Parentheses and brackets - Parentheses
Spelling
Part III. Style 20 spelling

Parentheses usually set off explanatory or interrupting elements of a sentence, much like paired commas (see 21.2) and dashes (21.7.2). In general, use commas for material closely related to the main clause, dashes and parentheses for material less closely connected. The abbreviations e.g. and i.e., which may introduce a clarifying comment (see 24.7), are used only in parentheses or in notes.

The conference has (with some malice) divided into four groups.

Each painting depicts a public occasion; in each—a banquet, a parade, a coronation (though the person crowned is obscured)—crowds of people are pictured as swarming ants.

There are tax incentives for “clean cars” (e.g., gasoline-electric hybrids and vehicles powered by compressed natural gas and liquefied propane).

Parentheses can also be used with citations (see chapters 16 and 18) and to set off the numbers or letters in a list or an outline (see 23.4.2).