Scientific American, Winning Science Fair Projects, Grades 5-7 Autor Bob Friedhoffer dec 2017 Paperback Preț: 65.39 lei 43-57 zile
Scientific American, Simple Science Fair Projects, Grades 3-5 Autor Bob Friedhoffer 3 iul 2018 Paperback Preț: 65.39 lei 43-57 zile