UK Traffic Signs Manual - Chapter 3 Regulatory Signs. 2008 (Second Impression 2008)-
Diagram 960; Fira Sans substituted for proprietary font used for text in the original
Source file supplied as EPS to uploader from Department for Transport; https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/223943/traffic-signs-manual-chapter-03.pdf
Department for Transport (United Kingdom)
Department for Regional Development (Northern Ireland)
Scottish Executive
Welsh Assembly Government