@BOOK{NAP12338, title = "On Mixed Launch Fleet Strategy and Policy Option: Letter Report", doi = "10.17226/12338", url = "https://nap.nationalacademies.org/catalog/12338/on-mixed-launch-fleet-strategy-and-policy-option-letter-report", year = 1987, publisher = "The National Academies Press", address = "Washington, DC" }