@BOOK{NAP18693, author = "National Research Council", title = "The Invisible University: Postdoctoral Education in the United States. Report of a Study Conducted Under the Auspices of the National Research Council. [Richard B. Curtis, Study Director]", doi = "10.17226/18693", url = "https://nap.nationalacademies.org/catalog/18693/the-invisible-university-postdoctoral-education-in-the-united-states-report-of-a-study-conducted-under-the-auspices-of-the-national-research-council-richard-b-curtis-study-director", year = 1969, publisher = "The National Academies Press", address = "Washington, DC" }