Henry Gordon Rice. Classes of Recursively Enumerable Sets and Their Decision Problems. Transactions of the American Mathematical Society (American Mathematical Society). 1953, 74 (2): 358–366. JSTOR 1990888. doi:10.2307/1990888.
Henry Gordon Rice. Classes of Recursively Enumerable Sets and Their Decision Problems. Transactions of the American Mathematical Society (American Mathematical Society). 1953, 74 (2): 358–366. JSTOR 1990888. doi:10.2307/1990888.