One of the better published account is by William C. Oates, The war between the Union and the Confederacy and its lost opportunities. He includes a chapter on this topic; in his opinion it was one of the "lost opportunities" of the Confederacy. As a Confederate officer who lost an arm in battle and served as a company and field officer of the Army of Northern Virginia for four years, Oates gets very little attention on this topic.

Service records sometimes include letters written by officers who wanted to recruit and lead black troops under the law passed in March 1865. These are found in actual service files and I'm only mentioning them from memory. On the opposite side, I've seen discharges in Alabama regiments for soldiers because they were of 'mixed blood;' again from memory.

For opinions of soldiers, the easiest route would be to get a copy of the Durden book and then find the newspapers that he cites. Soldiers submitted "letters to the editor" on this topic, and it's hard to argue with what they wrote. That's really what his entire book is about; the debate in Southern newspapers on whether or not black soldiers (slave or not) should be used. In my opinion, unless the writer lived inside Southern lines during the war, I don't see why anyone would bother with what other people (you may guess that I mean Yankees) wrote about it.