Sources
Every source backing a fact on Paul Hekkert's own page, deduplicated — the same source backing several facts appears once.
- https://dl.acm.org/doi/proceedings/10.1145/1409240 — https://dl.acm.org/doi/proceedings/10.1145/1409240
Every source backing a fact on Paul Hekkert's own page, deduplicated — the same source backing several facts appears once.