. "Catalysis of the hydrolysis of ester linkages within ribonucleic acids by removing nucleotide residues from the 3' or 5' end to yield 5' phosphomonoesters." . . . "exoribonuclease activity, producing 5'-phosphomonoesters" . "exoribonuclease activity, producing 5' phosphomonoesters" . . . . . . . .