Kitab al-Athar - Abu Yusuf Ya'qub ibn Ibrahim al-Ansari (182H)

The Book of Āthār is a collection of traditions of Abu Haneefa, narrated by Abu Yusuf on his authority, and it includes a chain of Hadiths that Abu Haneefa relied on in some of the rulings and fatwas he deduced, in addition to another collection of fatwas of At-Tabi’een among the jurists of Kufa and Iraq.

Very good edition, checked and thoroughly annotated.