I have gone through a lot of trouble trying to learn about the Early Buddhist Schools and what they believed. The Wikipedia entries, while helpful as a beginning point, are highly inaccurate.
For example, “Buddhas teach all dharmas with a single sound.” is listed in wikipedia. On closer inspection from scholarly sources, its actually “Every word uttered by the Buddha moves the Wheel of Dharma”(paraphrase).
Then another is this
The Samayabhedoparacanaćakra of Vasumitra regards the Ekavyāvahārikas, Gokulikas, and Lokottaravādins as being doctrinally indistinguishable
When, in reading articles, The Lokottaravadans held that the Supramundane aspects of the Buddha were substantially real, and mundane aspects were nominal, while the Ekavyavaharikas held both the Supramundane and mundane aspects of the Buddha were nominal. This, at least to me, seems to be matters of doctrine that lead to major differences in interpretation and practice.
Then on further reading of another source, it was said that instead of the Buddha, the Lokottaravans held the 4 Noble Truths were substantially real, while the Ekavyavaharikas held they were nominal. Yet even though one source said it was the 4 Noble Truths, they may have also believed these things about the Buddha as well.
A compendium?/encyclopedia/guide for access to all information related to the 18 Early Buddhist schools and their doctrinal differences backed by scholarly reference, as well as apparently, other minor extra schools called ‘External Schools’.
Understanding the differences between each sub school and what they actually believed, would be very useful for study of the EBTs
