NRaD TD1064

Writing and Editorial Guidelines

Revision 1

July 1994


1. Showing Possession

Use an apostrophe to form the possessive.

In singular nouns:

In plural nouns:

NOTE: It is acceptable to make an inanimate object possessive (e.g., the machine's specifications). Authors objecting to this practice may write the specifications of the machine or the machine specifications.

2. Pluralizing Dates and Abbreviations

Do not use an apostrophe to form the plural of a date or an all-capital abbreviation.


3. Enclosing Matter in Math

In math, use brackets, [ ], to denote enclosed matter treated as a unit. Use braces, { }, when necessary in long equations. Make sure the brackets and braces are long enough to contain the enclosed mathematics.

4. Parenthecizing Material Within Parentheses

In text, use brackets as parenthetic marks within parentheses ([ ]).

5. Adding Editorial Comments

When quoting material, use brackets to enclose corrections, omissions, explanations, editorial comments, or interpolations not specifically a part of the original quotation.


6. Listing Examples

Use bullets to draw attention to examples.

7. Using Numbers or Bullets

If a list has sequential significance or will be referenced, use numbers or letters to enumerate the items.

Three assistants were chosen:

If only a representative sample of items is listed, use bullets.

Here are just a few of the many beneficial features of the new budget cut:


8. Introducing Series

Use a colon after a complete sentence that introduces a list or series of items.

Expressions such as the following or as follows often precede a list.

Do not use a colon if the sentence is continuous without the colon.

9. Introducing Clauses

Use a colon to introduce a clause that explains, reinforces, or gives an example of a preceding clause or expression.


10. Separating Items in a Series

Use commas between items in a series.

Use a comma before a final conjunction (and, or, or nor) to show that the final item is of equal value to the other items and not part of a set of the last two items.

11. Separating Introductory Phrases

Use a comma after an introductory adverbial clause.

Use a comma after an introductory infinitive phrase.

Use a comma after a short introductory phrase to prevent confusion or misreading.

12. Enclosing Appositives and Nonrestrictive Clauses

Use commas to enclose appositives.

Use commas to set off a nonrestrictive clause (which is mainly descriptive and could be dropped without changing the reference of the noun).

Nonrestrictive (nondefining):

Do not use commas to set off a restrictive clause (which limits the reference of the noun in a way that is essential to the meaning of the sentence).

Restrictive (defining):

13. Separating Independent Clauses

Use a comma between independent clauses (complete thoughts) joined by the coordinating conjunctions and, but, or, and yet.

14. Using One Subject with Two Verbs

Do not use a comma to separate the subject from the second verb.


15. Punctuating Numerals

In numbers of more than four digits, use a comma between each group of three digits.

In numbers of two to four digits, omit the comma.

(See section on Numerals for more information.)

16. Punctuating Dates

In text, use a comma to separate the month and day from the year. (No comma is needed for day/month/year format.)


Use a comma to separate the year from the following text.

17. Punctuating Addresses

Use a comma to separate the city from the state.

Use a comma to separate the state from the following text.

Do not use a comma to separate the state from the zip code.


The most commonly used dash is the em dash, which, in typing, is designated by two hyphens. In the following material, the em dash is referred to simply as a dash.

18. Representing a Dash in Typed Copy

Use two hyphens set tight to represent a dash when preparing copy on a typewriter. Do not add a space before or after the dash.

19. Showing Sudden Break in Thought

Use a dash to mark a sudden break or shift in thought. Use sparingly.

20. Setting Off a Series of Appositives

A dash may be used to set off a series of appositives.

21. Using the En Dash

The en dash is longer than a hyphen and about half the length of an em dash. (When typing, use the hyphen with a space before and after it to denote an en dash.)

Use an en dash to indicate continuing, or inclusive, numbers (dates, times, or reference numbers).


Use an en dash to connect two coordinate elements.


22. Indicating Omitted Words

Ellipses indicate that words have been omitted from quoted material. Use three spaced periods to indicate missing words at the beginning or middle of a sentence.

If one or more words are omitted at the end of a sentence, use three spaced periods followed by the necessary end punctuation for the sentence as a whole.

Hyphen (See section on Compounds.)


23. Setting Off Subordinate Material

Use parentheses to set off material not part of the main statement or not a grammatical element of the sentence, yet important enough to be included.

24. Marking Items in a List with Numbers or Letters

Use parentheses to enclose numbers or letters that mark items in a list.

NOTE: Parentheses should always be used in pairs, not singly.

25. Enclosing Text Citations

Use parentheses to enclose text citations of references, figures, tables, and other pages.

26. Punctuating Sentences Within Parentheses

Do not capitalize the first word of a sentence enclosed in parentheses within a sentence.

Omit the end punctuation in a sentence enclosed in parentheses within a sentence.


If the parenthetical matter is a separate, stand-alone unit, capitalize the first word and place the end punctuation inside the closing parentheses.


27. Omitting Periods

Do not use periods after the following:

capital-letter abbreviations of military ranks and government agencies


Omit the period after:

28. Punctuating Figure Captions and Table Titles

Use a period in figure captions and table titles.

29. Punctuating Lists

In lists, use periods after entries that consist of a sentence, but omit periods after phrases or single-word items. If any entry requires a period, all other entries should also be written to be full sentences that end in a period. Note that it is preferable to make lists parallel--all phrases, all sentences.

He needed four things at the store:


Her principles of success are simple:

Quotation Marks

30. Using Material from Other Sources

Use quotation marks to indicate exact material derived from another source. (See section on References.)

31. Emphasizing Words and Phrases

Avoid using quotation marks for emphasis.

32. Quoting Within Quotations

Use single quotation marks for a quotation within a quotation.

33. Punctuating Within Quotations

Always place a period or comma within closing quotation marks.

Always place a colon or semicolon outside quotation marks.

34. Signaling Special Usage of a Word or Expression

Do not use quotation marks to enclose expressions following such terms as called, known as, and so-called unless such expressions are misnomers or slang.



35. Punctuating a Series Containing Internal Punctuation

Use a semicolon to separate items in a series containing internal punctuation.

36. Separating Independent Clauses

Use a semicolon to separate an independent clause containing a list of examples from the preceding independent clause when the list is introduced by words such as that is, for example, and for instance.

Use a semicolon to separate independent clauses not joined by a coordinate conjunction (and, but, or).

NOTE: If the clauses of a compound sentence are very long or are themselves subdivided by commas, you may use a semicolon between the clauses (even if they are joined by a conjunction).

Use a semicolon to separate independent clauses joined by a transitional connective (also, however, moreover, nevertheless, then, thus, for example, in fact).

Slant (Slash)

37. Replacing Common Conjunctions

Avoid using the slant between words in text to replace a common conjunction.