The archival materials are categorized by: projects; designs by others and documentation.

The projects make up the bulk of the archival records. The project files are again divided into dated projects, undated projects and unidentified projects. The dated projects are arranged chronologically; the undated ones are classified by (place) name when possible, and the last subheading is classified by type of design.

The drawings and photographs are thus described, as far as possible, by project. In the absence of a list of works, the information provided by the archival material was relied upon in the first instance. Secondly, the project descriptions were supplemented with data from the literature. These additions have been placed in square brackets. The numbers, which Rueter occasionally assigned to his designs, are included in the descriptions in (round) brackets. Literally quoted names and texts on the material are italicized in the descriptions.

Sometimes names of contractors (companies) are mentioned on the back of the photographs; these are not included in the descriptions. Of most photographs, the photographer is unknown. Of a limited number of photographs the photographer is known, these are: W. Brok (Hilversum); J. v. Faassen (Bussum-Laren); J. de Haas (Hillegom); H.F. van Hanja (Bussum); H.D. Henning (Amsterdam); B.Jb. Hoetink (Warnsveld); Fotopersbureau "Holland" (Amsterdam); H. Lugt (Almelo); J.H. Martelhoff (Amsterdam); H. Spies; C. Verschuur (Bussum); Bureau Vogt & Peets (Amsterdam); B.A. de Vries (Hattem); Van Winsen (Utrecht). These are not included separately in the descriptions. However, an *(asterisk) indicates from which photograph(s) the photographer is known. As an index (page 27) a list of photographers with the numbers of the photographs has been added.

Among the archival materials, work by other architects was also found namely by: H.A. v. Anrooy; W.C. Bauer and D.F. Tersteeg (garden architect); J. v. Campen; D. Hoeksema; G. v. Leeuwen (organ builder); H.F. Sijmons. Most notable is the work of H.A. van Anrooy. The literature shows that Van Anrooy was employed by Rueter. Perhaps this explains why some pieces by Van Anrooy were found among these archival materials. In 1918, Van Anrooy was a member of the editorial board of the periodical Wendingen, and he provided the magazine's cover in June.