Bismillah
Thank you for your question. Jurisprudence according to the school of Ahl al-Bayt is sometimes referred to as Ja'fari fiqh due to its basis primarily in the copious traditions narrated from Imams al-Baqir and al-Sadiq. While Imam al-Sadiq (as) did not write any books, he expounded jurisprudence in many reports that are narrated from him in mos matters of jurisprudence.
May you always be successful