The fonds consists of personal and professional materials created and collected by Sybren de Jong. The fonds is divided into five series:
• Publications (1940-1975)
• Lectures and Course Notes (1944-1975)
• Projects series (1955-1966)
• The Professional Life series (1960-1977)
• The Photographs series (1954)

This fonds contains drafts and blank copies of final exams for civil engineering courses Ruus taught while at UBC. Also included are notes, correspondence, and drafts relating to his various published papers and co-authored monograph.