ISO 286-2:2010(en), Geometrical product specifications (GPS) — ISO code system for tolerances on linear sizes — Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts
International Tolerance (IT) Grades table reference ISO 286
Old rules UNE under new GPS philosophy: standards in ISO 286-1/2: 2010 - MetalWorking
Principles of Tolerancing | Engineering Design - McGill University