The following excerpts are from Cyress Stearns' pioneering work The Buddha from Dolpo.
 

The Tibetan Master Dolpopa Sherab Gyaltsen "was one of the most important and original thinkers in Tibetan history," who "emphasized two contrasting definitions of the Buddhist teachings of emptiness: 'emptiness of self-nature,' which applies only to the level of absolute truth.  Dolpopa identified ultimate reality as the Buddha-nature inherent in all living beings.  This view of an 'emptiness of other,' known in Tibetan as Zhentong , is Dolpopa's main spiritual legacy.

References:   Stearns, Cyrus (1999). The Buddha from Dolpo: A Study of the Life and Thought of the Tibetan Master Dolpopa Sherab Gyaltsen. State University of New York Press. ISBN 0-7914-4191-1 (hc); ISBN 0-7914-4192-X (pbk).

Dolpopa and Other Related Links:

Jonang Foundation  

Wikipidia: Dolpopa Sherab Gyaltsen

Early Jonangpa in Tibet

 Adyashanti