From BS 1192 and PAS 1192 to ISO 19650. More information can obtained from this link: https://www.thenbs.com/knowledge/from-bs-1192-to-iso-19650-and-everything-in-between- Also the ISO document can be purchased here: Part 1 - https://www.iso.org/standard/68078.html Part 2 - https://www.iso.org/standard/68080.html