Dimension and Member Names in Calculation Scripts, Report Scripts, Formulas, Filters, and Substitution Variables
In substitution variable values, calculation scripts, report scripts, filter definitions, partition definitions, or formulas, you must enclose member names in brackets ([]) when used within MDX statements and in quotation marks (" ") for block storage databases, in these situations:

The name starts with one or more numerals (for example, 100).

The name contains spaces or these characters:

ampersand ( & )

asterisk ( * )

at sign ( @ )

backslash ( \ )

braces ( { } )

colon ( : )

comma ( , )

dash, hyphen, or minus sign (  )

exclamation point ( ! )

equal sign ( = )

greater than sign (
>
) 
less than sign (
<
) 
parentheses ( )

percent sign ( % )

period ( . )

plus sign ( + )

semicolon ( ; )

slash ( / )

tilde ( ~ )

In calculation scripts and formulas, enclose member names that are also Essbase keywords in quotation marks (" ") for block storage databases, and in brackets ([ ]) for aggregate storage databases including these member names:
BEGIN DOUBLE ELSE END FUNCTION GLOBAL IF MACRO MEMBER RANGE RETURN STRING THEN
Enclose in quotation marks names, in calculation scripts, report scripts, or formulas, that contain or start with spaces or these characters: +  * / ( ) : , @ ; ) { } [ ] <
Also enclose in quotation marks names that start with numbers. For example:
@SUM(ac1, "12345");