Jeffry D. Wert, "Trimble, Isaac Ridgeway," American National Biography Online, February 2000, http://www.anb.org/articles/05/05-00792.html.
[Isaac] Trimble was one of the oldest combat officers of the Civil War. Despite his age, he had a distinguished record, noted for personal bravery, combativeness, and skill. A southerner by birth, he never questioned the rightness of the Confederate cause and devoted himself to it. He was perhaps Maryland's finest soldier in the conflict.