3 ms·
I remember a discussion about this on MathOverlow http://mathoverflow.net/questions/26267/where-to-buy-premium-white-chalk-in-the-u-s-like-they-have-at-rims htt
by quasiresearcher 11y ago
I remember a discussion about this on MathOverlow http://mathoverflow.net/questions/26267/where-to-buy-premium-white-chalk-in-the-u-s-like-they-have-at-rims http://mathoverflow.net/questions/26267/where-to-buy-premium...
- monochromatic 11y agoI remember that being linked from this article.