@BOOK{NAP11525, author = "Transportation Research Board and National Research Council", title = "Polar Icebreaker Roles and U.S. Future Needs: A Preliminary Assessment", isbn = "978-0-309-10069-4", doi = "10.17226/11525", url = "https://nap.nationalacademies.org/catalog/11525/polar-icebreaker-roles-and-us-future-needs-a-preliminary-assessment", year = 2005, publisher = "The National Academies Press", address = "Washington, DC" }