Neurophysiology of learning in adults:
Cozolino and Sprokay. 2006. Chapter 2: Neuroscience and adult learning. NEW DIRECTIONS FOR ADULT AND CONTINUING EDUCATION, no. 110.
DOI: 10.1002/ace.214Career change: a midlife PhD
Never too late:
Best colleges for older students:
Age limits for grad students?
Benefits and disadvantages of being an older student:
Benefit of getting a PhD: