Wikipedia
The Abhidharmakośakārikā or Verses on the Treasury of Abhidharma is a key text on the Abhidharma written in Sanskrit verse by Vasubandhu in the 4th or 5th century. It summarizes the Sarvāstivādin tenets in eight chapters with a total of around 600 verses. The text was widely respected and used by schools of Buddhism in India, Tibet and East Asia.
Vasubandhu wrote a commentary to this work called the Abhidharmakośabhāsya. In it, he critiques the interpretations of the Sarvāstivādins, Vaibhāṣikas and others of the tenets he presented in his previous work from a Sautrāntika perspective. This commentary includes an additional chapter in prose refuting the idea of the "person" (pudgala) favoured by some Buddhists of the Pudgalavada school. However, later Sarvāstivādin master Samghabhadra considered that he misrepresented their school in the process, and at this point designated Vasubandhu as a Sautrāntika (upholder of the sutras) rather than as an upholder of the Abhidharma.