In "The work of Tate" Milne says:



> 
> "The relation between the two conjectures has been greatly clarified by the work
>  of Deligne. He defines the notion of an absolute Hodge class on a (complete smooth)
>  variety over a field of characteristic zero, and conjectures that every Hodge class on
>  a variety over C is absolutely Hodge. The Tate conjecture for a variety implies that
>  all absolute Hodge classes on the variety are algebraic. Therefore, in the presence of
>  Deligne’s conjecture, the Tate conjecture implies the Hodge conjecture. As Deligne
>  has proved his conjecture for abelian varieties, this gives another proof of Piatetski-
>  Shapiro’s theorem."
> 
> 
> 


In which work (articles) Deligne shows this conjecture?


Is there some book (or expository article) about this conjecture and its connections with Tate and Hodge conjectures?



Reference request: Deligne's conjecture (cycles)
Deligne, *Hodge Cycles on Abelian Varieties*, in Hodge Cycles, Motives, and Shimura Varieties,
Lecture Notes in Math. 900, 1981, pp. 9-100. Maybe you could use Google to find these references by yourself?


