9.
The Chapter on Searches
1-10.
The Ten Discourses Beginning with Searches
451-460. "There are these three searches, monks. Which three? Sensual seeking, seeking existence, seeking the holy life" - this should be expanded.
The Search Chapter is the ninth.
Its summary:
Search, discrimination, mental corruption, existence and suffering, three;
Barrenness, stain, and trouble, feeling, craving, and with thirst.