lispdoc - results for both-case-p

(both-case-p char)
Function: The argument must be a character object. BOTH-CASE-P returns T if the argument is an alphabetic character and if the character exists in both upper and lower case. For ASCII, this is the same as ALPHA-CHAR-P.
 Mentioned in:
CLtL2 - 13. Characters
CLtL2 - 13.2. Predicates on Characters
HyperSpec - Function UPPER-CASE-P, LOWER-CASE-P, BOTH-CASE-P