Secret codes /
Beatty, Ken,
Secret codes / Ken Beatty. - v, 76 pages : color illustrations ; 21 cm + 2 CD - Penguin readers ; level 4 .
1405852224 9781405852227
Readers--Cryptography.
--Reading book
428.6 / BEA
Secret codes / Ken Beatty. - v, 76 pages : color illustrations ; 21 cm + 2 CD - Penguin readers ; level 4 .
1405852224 9781405852227
Readers--Cryptography.
--Reading book
428.6 / BEA