Any Suggestions for Readings on Modern Ethiopia?

All right this is a serious post, but it is short. Are there any good histories of Ethiopia under Mengistu written in English? I would like to find a political history on the regime written using archival and oral sources. But, I am not sure where to look. Did the government that succeeded Mengistu even open up the archives? What about Eritrea, have they allowed access to archives regarding the reign of Mengistu? I know all these questions sound really basic. But, it occurred to me that Ethiopia under Mengistu was the one African state that sought to emulate the USSR under Stalin. Yet, I know very little about the actual details of the regime. Most of what I do know comes from material written during the 1980s when Mengistu was still in power and access to the archives an obvious impossibility.