The researcher said:

‘With respect to true tawḥīd and that which opposes it with respect to shirk, and knowing such shirk and cautioning against it, there is no absolute mention of it in their books of creed, and I don’t know where they have (addressed the issue)?  Is it in the books of furū? It is not in such books! Or have they abandoned this cause altogether? The latter is that of which I am certain’.

I say:

The Ash'aris or True Tawhid and Shirk
Shaykh Salah al-Din al-Idlibi