@inbook {MATHEDUC.02342481,
author = {Buys, Kees and Neumann, Dagmar},
title = {Focussing on mental arithmetic.},
year = {2001},
booktitle = {Proceedings of the 25th conference of the international Group for the Psychology of Mathematics Education. Vol. 1},
isbn = {90-74684-16-5},
pages = {272},
publisher = {,},
msc2010 = {F30xx},
identifier = {2001f.04948},
}