Which landmark paper first described the differentiation of T-cells?
This paper appears to be a history of the discovery of B/T differentiation and the role of the thymus. I believe that you should find a number of important references therein.
It describes specifically a series of publications in the 1950s and 1960s that may be relevant (section &quot;Identification of T and B cells&quot;), such as this one by Gowans.