^Pan, C.-D., Wang, Y., & Ding, X. (1975). On the representation of every large even integer as a sum of a prime and an almost prime. Scientia Sinica, 18(5), 599–610.
^Chen, J. R. (1973). On the representation of a larger even integer as the sum of a prime and the product of at most two primes. Scientia Sinica, 16(2).