The counters available in a particular notebook are usually defined by the stylesheet. The default stylesheet defines counters named "Section", "Subsection", "Subsubsection", "Equation", "Figure", and "Table".
Counter values can be displayed either as they exist at the location of the display or as they exist at a remote location defined by a cell tag.
A counter named "Page" is always available, but it is only valid when the option to show page breaks is turned on.
