The structure of P-TEFb (CDK9/cyclin T1), its complex with flavopiridol and regulation by phosphorylation. - Baumli, S; Lolli, G; Lowe, E; Troiani, S; Rusconi, L; Bullock, A; Debreczeni, J; Knapp, S; Johnson, L (EMBO journal, 2008)