which museum exhibits the the baptism of christ by piero della francesca ?
select distinct var_uri where brack_open dbr_The_Baptism_of_Christ_ attr_open Piero_della_Francesca attr_close dbo_museum var_uri sep_dot dbr_The_Baptism_of_Christ_ attr_open Piero_della_Francesca attr_close dbo_author dbr_Piero_della_Francescabrack_close