The Tipiṭaka in Three Languages

Hetudukaparittattika

Abhidhammapiṭaka · Paṭṭhāna (5) · Vol. 44 · Section 571

[571] A phenomenon (dhamma) that is a root (hetu) and immeasurable (appamāṇa) is a condition for a phenomenon that is a root and immeasurable by root condition (hetu-paccaya): three.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 5 other places