The rules that use the category "<det-sing>" are:

<item-not_call_sign>

<det-sing> <item_n-sing>

<det-sing> <item_n-sing> <point_location_mod-gapsout_null-gapsin_null>

<target_description>

<det-sing> <target_nom-sing>

<discourse_det-sing>

<det-sing>