+Note that the @code{\paper} variables discussed in this section do
+not control the spacing of staves within individual systems.
+Inter-system spacing is controlled by grob properties, with
+settings typically entered inside a @code{\score} block, and not
+inside a @code{\paper} block. See
+@ref{Vertical spacing between systems}.
+
+
+@subsubheading Structure of spacing alists for @code{\paper} variables
+
+Each of these variables is an alist (associative list) containing
+four @emph{keys}: