@inbook{00ad08363b3741ed9f23b40337459396,
title = "Challenging problems: Mathematical contents and sources",
keywords = "Fibonacci sequence, Mathematics education, Problem arithmetic, Problem geometry, Secondary student",
author = "Vladimir Protasov and Mark Applebaum and Alexander Karp and Romualdas Ka{\v s}uba and Alexey Sossinsky and Ed Barbeau and Peter Taylor",
year = "2009",
doi = "10.1007/978-0-387-09603-2_2",
language = "English",
series = "New ICMI Study Series",
publisher = "Springer",
pages = "11--51",
booktitle = "New ICMI Study Series",
address = "Germany",
}