The rules that use the vocabulary item "sp" are:

<i_f_v-sing>

sp 82mm mortar

sp eighty two mortar

<i_f_v-pl>

sp 82mm mortars

sp eighty two mortars

<sp>

sp

<i_f_v>

sp 82mm mortar

sp 82mm mortars

sp eighty two mortar

sp eighty two mortars