The Path of Kulaynī to Zurārah
From the reliable Uṣūl works is the book of Zurārah. He himself is very trustworthy and is from the companions of Imam Bāqir and Ṣādiq (a).
Sometimes Shaykh Kulaynī mentions Zurārah without a path in al-Kāfī, such as in Kitāb al-Zakāt, pg. 520 and 526.
Other times he does mention his path to Zurārah in the following manner:
علي بن ابرهيم عن أبيه عن حماد بن عيسى عن حريز بن عبدالله عن زرارة
‘Alī b. Ibrāhīm from his father from Ḥammād b. ‘Īsa from Ḥarīz b. ‘Abdillah from Zurārah. Like on page 520. Most of what Kulaynī narrates from Zurārah is from this path.
The Path of Ṣadūq to Zurārah
أبوه عن عبدالله بن جعفر الحميري عن محمد بن عيسى بن عبيد و حسن بن طريف و علي بن إسماعيل عن حماد بن عيسى عن حريز عن زرارة
From his father, from ‘Abdillah b. Ja’far al-Ḥimyari from Muḥammad b. ‘Īsa b. ‘Ubayd and Ḥasan b. Ṭurayf and ‘Alī b. Ismā’īl, all of them from Ḥammād b. ‘Īsa, from Ḥarīz, from Zurārah.
Then Ṣadūq says: And likewise, that which is in it from Ḥarīz b. ‘Abdillah, I have narrated it with this chain. Likewise, that which is in it from Ḥammād b. ‘Īsa.
The Books of Hishām b. Ḥakam
From the Uṣūl that are reliable are the books of Hishām b. Ḥakam. He himself is highly trustworthy and is from the companions of Imam Sadiq and Kathim (a).
The path of Kulaynī to Hishām
علي بن إبراهيم عن أبيه و محمد بن إسماعيل عن فضل بن شاذان جميعاً عن ابن ابي عمير عن حشام بن الحكم
‘Alī b. Ibrāhīm from his father and Muḥammad b. Ismael from Fadhl b. Shadhan (all of them) together from Ibn. Abi ‘Umayr from Hishām b. Ḥakam.
This chain is found al-Kafi in the chapter of Fitrah, page 171 and Kitab al-Iman page 75. Sometimes Kulayni narrates from him regarding the rational arguments for not being able to see Allah. Such is found in the end of the chapter of Ibtāl al-Ru’ya.
The path of Saduq to Hisham (in the last part of Man la-Yahdhuru al-Faqih):
أبوه و محمد بن حسن عن سعيد بن عبدالله و حميري جميعاً عن أحمد بن محمد بن عيسى عن علي بن الحكم و محمد بن أبي عمير جميعاً عن هشام بن الحكم
From his father and Muhammad b. Hassan from Sa’d b. Abdallah and Himyari (all of them) together, from Ahmad b. Muhammad b. Isa from Ali b. Hakam and Muhammad b. Abi Umyar, together from Hishām b. Ḥakam.
The paths of Shaykh Tusi to Hisham (In his Fihrist):
جماعة عن صدوق عن ابن الوليد عن الصفار عن يعقوب بن يزيد و محمد بن الحسين بن أبي الخطاب عن ابن أبي عمير و صفوان بن يحيى عنه
A group of people, from Saduq, from ibn Walid, from Saffar, from Ya’qub b. Yazid and Muhammad b. Hussayn b. Abi Khattab, from ibn Abi Umayr and Safran b. Yahya from him (Hisham).
جماعة عن أبي المعضل عن حميد عن عبيدالله بن احمد بن نهيك عن ابن أبي عمير عنه
A group of people, from Abi Mufadhal, from Hamid, from Ubaydallah b. Ahmad b. Nahik, from Ibn. Abi Umayr from him (Hisham)
 Kitab al-Istiṭā’ah wa al-Jabr. Other untitled books are also attributed to him
 Ashab al-ijma, there is no difference of opinion regarding his status and trustworthiness
 Ibrahim b. Hashim
 This was a popular debate between the early Muslims relating to whether one is physically able to see God.