GCD of a list of integers : lgcd

lgcd has a list of integers (or of a list of polynomials) as argument.
lgcd returns the gcd of all integers of the list (or the gcd of all polynomials of the list).
Input :

lgcd([18,15,21,36])

Output :

3

Remark
lgcd does not accept two lists (even if they have the same size) as arguments.