@BOOK{NAP12414, title = "Conference on Potential Hazards of Back Contamination from the Planets", doi = "10.17226/12414", url = "https://nap.nationalacademies.org/catalog/12414/conference-on-potential-hazards-of-back-contamination-from-the-planets", year = 1964, publisher = "The National Academies Press", address = "Washington, DC" }