@BOOK{NAP18913, author = "National Research Council", title = "Annual Review of U.S. Progress in Rock Mechanics: Rock Mass Characterization", doi = "10.17226/18913", url = "https://nap.nationalacademies.org/catalog/18913/annual-review-of-us-progress-in-rock-mechanics-rock-mass", year = 1983, publisher = "The National Academies Press", address = "Washington, DC" }