Gaya APA

Nell, S., Langdale, P. (2008). PPR 261 Highways Agency 2007 National Falling weight Deflectometer Correlation Trials . : TRL.

Gaya MLA

Nell, S.., Langdale, P.. "PPR 261 Highways Agency 2007 National Falling weight Deflectometer Correlation Trials". : TRL, 2008. Text.