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 years if only the decade is cited.
Librarianship in the ’90s is a completely different field.
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.
University of Illinois–based
See also “dates” in the Numbers and Dates section.
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
offsite, onsite, overhead
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.
full-text electronic article
The electronic article was presented in full text.
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.
Jones then compared the aggregate data (over time) to discover subscription changes—those journals renewed, cancelled, or ordered.
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.”
Quotations that are longer than a sentence or thirty words, whichever is longer, should be set apart from the text as block quotations; do not use quotation marks.
Place periods and commas within quotation marks; place semicolons and colons outside them. Place quotation marks around the names of groups in surveys.
the “very satisfied” group
the group that was very satisfied
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: