Vélez de Cea, Abraham. "Emptiness in the Pali Suttas and the Question of Nagarjuna's Orthodoxy." Philosophy East & West 55, no. 4 (October 2005): 507-528.

Abstract

This essay attempts to clarify the position of Nagarjuna in the history of Buddhist philosophy by comparing the concept of emptiness in the Pali Nikayas and the Mulamadhyamakakarika. It is argued that the identity of samsara with nirvana, the emptiness of svabh?va of all dharmas, and the equating of emptiness and dependent arising are not revolutionary innovations of Nagarjuna or the second turning of the wheel of Dharma, but orthodox philosophical moves entailed by the teachings of early Buddhism.