Thomas Christy's Road across the Plains : a guide to the route from Mormon Crossing, now Omaha, Nebraska, to the city of Sacramento, California ... compiled from his personal observations during the spring and summer of 1850 by Thomas Christy of Van Buren County, Iowa : together with his diary of the same journey, edited and cartographically interpreted by Robert H. Becker, Bancroft Library, University of California, Berkeley, California.