MLA Style Manual
Never use an apostrophe after years to indicate a decade:
The film was made in the 1970s.
Do use an apostrophe before the year if only the decade is cited.
In typographical terms, the em dash (—) is a unit of measurement exactly as wide and high as the point size being set. So named because the letter "M" in early fonts was usually cast on a square body. The en dash (–) is one-half the width of an em.
Em dashes are used to set off elements of text with internal punctuation, and en dashes to indicate a numerical range or hyphenate an open compound:
The library is organized so that any question—whether
technical, reference, or circulation—can be answered by staff.
In MLA publications, en dashes are also used with institutional names that take the following form:
University of Wisconsin–Madison
In general, MLA style does not use hyphens after "non," "co," "pre," and other prefixes and "off," "on," and other prepositions when forming a compound word.
nonmember, coworker, prearrange
When deciding whether or not to hyphenate a compound word, follow the above guidelines and check the word in question in this manual. If it is not included there, see 7.85 on pages 375–84 of CMS16, "Hyphenation Guide for Compounds and Words Formed with Prefixes," for guidelines. A general principle is that two words forming an adjective before a noun use a hyphen, two words forming an adjective after a noun do not. See also "word division" in this section.
Within parentheses, use brackets. For overlapping parenthetical elements, combine parentheses with em dashes.
Jones collected aggregate data (how it compares to
itself [over time]) for his report.
Begin the first word of a quotation with a lowercase letter if it syntactically completes an author's sentence, even if the word in the original quotation began a sentence:
Smith completed his argument by noting that "this is a difficult question to examine in depth."
Place periods and commas within quotation marks; place semicolons and colons outside them. Place quotation marks around the names of groups in surveys.
A slash mark, virgule, or diagonal (/). Avoid using this mark in running text as a symbol for "or," "and," or "per"; for example, use "indexing or abstracting," not "indexing/abstracting." The names of some computer files or procedures, however, do require this symbol.
Use a forward slash at the end of URLs that refer only to subdirectories.
Consult MW11. In general, run a solitary vowel into the first line:
Medical Library Association
Last Updated: 2011 July 20