Osborn, Henry Fairfield, 1857-1935.; Wortman, Jacob Lawson.; Wortman Expedition to the Rocky Mountains (1st : 1891)(New York : Published by order of the Trustees, American Museum of Natural History, 1892)
Wortman, Jacob Lawson.; Wortman Expedition to the Rocky Mountains (3rd : 1893)(New York : Published by order of the Trustees, American Museum of Natural History, 1894)