Sources and original illustrations
Primary references and the limits of this educational collection.
Primary references
- IFAB — Law 11, offside — Position and involvement are separate parts of an offside decision; our paper observation exercises are original.
- IFAB — Law 9, ball in and out of play — The whole-ball boundary principle, not a comprehensive guide to every reason play stops.
- IFAB — Law 12, fouls and misconduct — A second caution in the same match leads to a sending-off; the incident timelines here are invented.
- IFAB — Law 3, players — The entry of a substitute completes the substitution; event-specific allowances and protocols need separate reading.
- IFAB — VAR protocol — Checks, reviews and the referee’s final decision are distinct stages.
- ITF — 2026 Rules of Tennis — The standard advantage-game loop and the alternative no-ad deciding point. The comparison diagrams and point sequences are original.
- FIBA — Official Basketball Rules 2026 v1.1 — Effective 1 October 2026: point values, distinct foul counters, quarter lengths and the separate shot clock. Arithmetic exercises are invented.
- USBC — Keeping Score — Strike and spare bonus-roll definitions. The frame sequences below are our own examples.
- World Netball — Centre Pass Checks — Centre passes alternate rather than being awarded to the side that conceded.
- World Netball — Rules of Netball 2024 — Goal Shooter and Goal Attack may score from within the goal circle; this is a narrow spectator primer.
- FIDE — Laws of Chess effective 2023 — Standard result points and clock operation. The arithmetic and display examples are original.
- United States Blind Chess Association — Chess Notation — English piece labels, file/rank square names and basic piece or pawn arrival notation. The short practice sequence is original, not the source’s reproduced sample game.
- USTA — Tennis Scoring: Points, Sets and Games — The distinct points, games, sets and match score units. The nested reading ladder and invented display are original.
- USTA — The AD-Inbox, officiating explanations — The first single service slot followed by alternating two-point blocks; no other questions or rulings from the mailbag are reproduced.
Original visual material
The diagrams in this edition are original SVG illustrations explaining the sequence or decisions in each guide. They do not show a laboratory experiment, a personal trip or a tested product result. No photographs from the linked sources are reproduced.
Check the source in context
References were consulted during preparation of this edition. A source may cover a broader or narrower question than a particular guide; the support notes above explain why it is listed. Read the original for methodology, exceptions and updates.