In the call number system using by the UNDA Library:
- 'F' stands for 'Folio' - these are books that are more than 32.6 cm in height.
- 'Q' stands for 'Quarto' - these are books that are more than 27 cm in height, but less than 32.6.
Because these items are taller than the majority of items in the collection (up to 27 cm), they are housed separately on shelving of different height. All the quartos are placed together on shelves labelled 'Q', and all the folios are placed together on shelves labelled 'F'.
