British Standards Institution. (1973). Specification for the construction of road traffic signs and internally illuminated bollards (2nd revision.). British Standards Institution.
Chicago-viite (17. p.)British Standards Institution. Specification for the Construction of Road Traffic Signs and Internally Illuminated Bollards. 2nd revision. London: British Standards Institution, 1973.
MLA-viite (8. p.)British Standards Institution. Specification for the Construction of Road Traffic Signs and Internally Illuminated Bollards. 2nd revision. British Standards Institution, 1973.
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