Sör Çepçevre'nin Matematik Maceraları : Çetre Adası /
by Cindy Neuschwander ; illustrated by Wayne Geehan.
- 1st ed.
- İstanbul : Doruk, 2014.
- 32 p. : col. ill ; 24 cm.
Young Per and her cousin Radius set out to unlock the secret of Immeter before the sea serpent finds them.