National Science Foundation (2006). "Time to Degree of U.S. Research Doctorate Recipients" (PDF). InfoBrief, Science Resource Statistics. NSF. 06-312: 7. Under "Data notes" this article mentions that the J.D. is a professional doctorate.
San Diego County Bar Association (1969). "Ethics Opinion 1969-5". Retrieved 2008-05-26.. Under "other references" differences between academic and professional doctorates, and contains a statement that the J.D. is a professional doctorate
German Federal Ministry of Education. "U.S. Higher Education / Evaluation of the Almanac Chronicle of Higher Education" (PDF). Archived from the original (PDF) on April 13, 2008. Retrieved 2008-05-26. Report by the German Federal Ministry of Education analysing the Chronicle of Higher Education from the U.S. and stating that the J.D. is a professional doctorate.
Stevens, R. (1971). "Two Cheers For 1870: The American Law School", in Law in American History, eds. Donald Fleming and Bernard Bailyn. Boston: Little, Brown & Co., 1971, p. 427.