13.1a Capitalization in abbreviations. [VI.27.a]

The double capital sign is used only where two or more capital letters in an abbreviation follow one another with no intervening periods. Following a period the appropriate capital or double capital sign is repeated. In abbreviations that contain both upper and lower case letters, it is suggested that each upper case letter be capitalized individually. Examples:

NATOY.W.C.A.LL.D.
MHzUSAirB.Sc.

As in the case of a hyphenated compound word, the double capital sign placed before a hyphenated compound abbreviation indicates that all the letters of the abbreviation are capitals, and the capital sign is not repeated after the hyphen. Such a compound abbreviation may be divided at the end of a line after the hyphen. Examples:

AFL-CIO

In a fully capilalized abbreviation, where each letter represents a word and is followed by a period, the entire abbreviation should be written on one line without a space between the separate letters. Example:

K. U. (Kansas University)