Digest / Building research establishment. 476 : Guide to machine strength grading of timber / C.Benham,C.Holland ,V.Enjily, 2003. - 12 p. - Текст : непосредственный.
Digest / Building research station. 492 : Timber grading and scanning / C.Holland, T.Reynolds, 2005. - 12 p. - Текст : непосредственный.