Deebbud,
the section your looking for 3.159 (5/08) duty to assist.
1. Competent. Medical evidence means evidence provided by a person who is qualified through education, training or experience to offer medical diagnoses, statements, or opinions. Competent medical evidence may also mean statements conveying sound medical principles found in MEDICAL TREATISE. It would also include statements contained in authoritative writings such as medical and scientific articles and research reports or analyses
i always wrote see section etc. duty to assist then I would type that section, number, it as evidence and provided a copy. I did this because no one could say oh I didn’t know, if it went to the highest court every piece of evidence would be in my file to support my claim.