Frank Edgar Farley, An Advanced English Grammar with Exercises
“ According to their use as parts of speech, subordinate clauses are adjective, adverbial, or noun clauses.I. ADJECTIVE CLAUSES 379. A subordinate clause that modifies a substantive is called an adjective clause (§ 47) . {Able men | Men of ability | Men who show ability} can always find employment. {Treeless spots | Spots without trees | Spots where no trees grew} were plainly visible. In each of these groups, a noun (men, spots) is modified (1) by an adjective, (2) by an adjective phrase, (3) by an adjective clause. The sense remains unchanged. ”
