Cyclic adenosine 5′-monophosphate and calcium induce CD152 (CTLA-4) up-regulation in resting CD4+ T lymphocytes, Vendetti, S., Riccomi A., Sacchi A., Gatta L., Pioli Claudio, and De Magistris M.T. , Journal of Immunology, Volume 169, Number 11, p.6231-6235, (2002)

Hormonal Regulation of T Cell Differentiation in Aging Mice, Doria, G., Baschieri Selene, Goso C., Brunelli R., Zichella L., Spanò M., Fattorossi A., D'AMELIO R., and Frasca D. , Annals of the New York Academy of Sciences, Volume 650, Number 1, p.121-124, (1992)