The Tipiṭaka in Three Languages

Suññatavāra

Abhidhammapiṭaka · Dhammasaṅgaṇī · Vol. 34 · Section 406

[406] What at that time is sustained thought (vicāra)? That which at that time is pondering (cāra), considering (vicāra), continued considering (anuvicāra), close considering (upavicāra), the mind's (citta) continuous connecting (anusandhanatā) and sustained observing (anupekkhanatā) — this at that time is sustained thought.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 5 other places