| RefNo | Title | Date |
| L/E/78/22 | Industrial Rhythm \ Hijmans' Report \ Charts | n.d. |
| L/E/75/26 | Industrial Rhythm \ Hijmans' Report \ Faure Pere et Fils Revin | n.d. |
| L/E/63/17 | Industrial Rhythm \ Extracts from a Letter from Ernst Hijmans | 1945 |
| L/E/75/27 | Industrial Rhythm \ Hijmans' Report \ Objectives | n.d. |