The Book of Occultation — al-Ṭūsī · Hadith 399 (#Ḥadīth #48)

فأما من قال إن للخلف ولدا وإن الأئمة ثلاثة عشر، فقولهم يفسد بما دللنا عليه من أن الأئمة عليهم السلام اثنا عشر. فهذا القول يجب إطراحه، على أن هذه الفرق كلها قد انقرضت بحمد الله ولم يبق قائل يقول بقولها، وذلك دليل على بطلان هذه الأقاويل.

As for the one who says that the successor has a son and that the Imams are thirteen, their assertion is invalid, because of our proofs that the Imams are twelve. Therefore, this assertion has to be discarded. Reminder: Besides, all these sects have perished, thanks to God, and there is not a person who would uphold any of these beliefs, and this itself is the proof of their falsity.

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).