A prepositional phrase heading consists of two or more nouns, with or without modifiers, linked by a preposition or prepositions. It is used to express complex relationships between topics which cannot be represented by a conjunctive phrase, or to represent a concept or thing only stated in the form of a prepositional phrase in the language. It is also used when there is an established pattern for similar headings. Examples

7.2123 Reference

See also:

7.212 Phrase headings