  We determine the smooth concordance order of the 3-stranded pretzel knots
P(p,q,r) with p,q,r odd. We show that each one of finite order is, in fact,
ribbon, thereby proving the slice-ribbon conjecture for this family of knots.
As corollaries we give new proofs of results first obtained by Fintushel-Stern
and Casson-Gordon.
