Your guide to Zion and Bryce CanyonMichael Oard, Tom Vail, Dennis Bokovoy, John Hergenrather · First published 2010Open the Tome
Road guide to Yellowstone National Park and adjacent areasHarold G. Coffin, John Hergenrather, Dennis Bokovoy, Michael J. Oard · First published 2005Open the Tome
