Gustafson emphasized documentation of the excavation and hired artists and photographers as well as engineers. This body of documentation is still considered an essential source of information.
Gustafson’s diaries and sketchbooks include:
- Two diaries in A5 format, 131 pages each.
- Book no. 1, dated 13 July to 31 July 1904.
- Book no. 2 – dated 2 August to 22 September 1904. - A sketchbook in folio format, unsystematically dated.
- A small sketchbook with a few drawings, also unsystematically dated.
In 2014, the diaries from the excavation of the Oseberg burial mound were incorporated into the registry of Norwegian documentary heritage – the Norwegian submission to UNESCO’s Memory of the World.
