Our main sources are personalities like Shaykh Kulayni, Shaykh Mufid, Sharif Murtada, Shaykh Tusi, Ibn Idris Hilli, Muhaqqiq Hilli, `Allama Hilli, Shaheed al-Awwal, etc. and all their works.
The most important output of the Safavi era scholars was more in the encyclopedic re-compilations of these earlier works into the collections of Wasa'il and Bihar, etc. But that said, most of the sources they used predated that by centuries, and for the most important of them, like Kafi, Faqih, and so on, we still have the original books themselves separate from the the encyclopedic works.
Bro I know but thats your scholars and their works, but Hisham b Hakam is during the time of 5th and 6th imams.He is much earlier than these scholars.
I think u r misunderstanding me as if the ideology of 12ers was formulated in the safavi times , that is not the case and I didnt mean to say that but the 12er becoming a state religion and its legal/political ramifications was formulated during this time.Esp the role of clergy in 12er shiaism and thats what the author talks about.