One boy described it in an undated letter to his mother.

The book has appropriately addressed, undated letters and forms ready for signatures.

In an undated letter he wrote to thank her:

Fitzwilliam wrote to his wife (in an undated letter) that the Reflections was "almost universally admired and approved".

On appointment, Lawrence gave Lloyd George a signed but undated letter of resignation.

In an undated letter to Cromwell, written before 1540, he begs to be relieved of his office, describing himself as feeble.

Bagby must have written more than a thousand of those undated weekly letters before he died.

It was an undated letter but I assume it was issued yesterday.

According to an undated letter, all that was not meant that way.

This undated letter is placed at the end of July, 1540 in Letters & Papers.