Lovely old small books, ideal size for tucking into a display or topping an existing stack.
These smaller size books are not the easiest to find now days.
Dark Bue "Hymns" Book - 10.5 x 8cm (1916)
Mid Blue "The Saviour King" 10 5 x 10cm (1910)
Although I cannot find publishing dates, the green appears to be considerably older.
These are a great addition to your display- pop them in an old box or bowl, in the top of some od scales or lay them open on a shelf or existing book stack.