The Book of Occultation — al-Ṭūsī · Hadith 355 (#Ḥadīth #4)
Chapter 33 | Imamate of Imam Hasan Askari
166- وروى يحيى بن بشار القنبري قال: أوصى أبو الحسن عليه السلام إلى ابنه الحسن عليه السلام قبل مضيه بأربعة أشهر،وأشهدني على ذلك وجماعة من الموالي.
H 166 - Yahya bin Bashr Qambari has narrated that Abul Hasan Imam Hadi , four months before he passed away, made bequest to his son, Hasan and I and a group of Shia witnessed it.
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).