Jefferson Davis was the president of the Confederate States of America from 1861 to 1865, the Civil War period. This stamp is a primary source because it was in use during Davis' presidency.
This 1967 stamp is a secondary source that depicts Davy Crockett, both a real person and a "mythical" character from the 19th century American West. "Mythical" because his heroic adventures have become larger than life in the annals of American history making it hard to know the difference between reality and myth.
Author Samuel Clemens (also known as Mark Twain) lived in the 1800s and travelled the American West by stagecoach, writing about it in his book, "Roughing It." Do you think this stamp is primary or secondary?