To specify a range, you append
/range-to(end-point)
to a location path specifying the start point of the range.
The parentheses contain a location path specifying the endpoint of the range.
For example, suppose you want to select everything
between the first PERSON element and the last
PERSON element
xpointer(/child::PERSON[position() = 1]/range-to(/child::PERSON[position() = last()]))