Alice

Perish By The Sword, 10.

We can find in a text only what is there to be found. However, every Poul Anderson text has a wealth of content. For example:

"'An un-birthday present.'" (p. 98)

- is a literary reference:

‘It’s a cravat, child, and a beautiful one, as you say. It’s a present from the White King and Queen. There now!’
‘Is it really?’ said Alice, quite pleased to find that she had chosen a good subject, after all.
‘They gave it me,’ Humpty Dumpty continued thoughtfully, as he crossed one knee over the other and clasped his hands round it, ‘they gave it me—for an un-birthday present.’
-copied from here, Chapter VI, Humpty Dumpty.

Quiz question: How many Alice references are there in Anderson? You can check here (scroll down) although not all blog references to Alice are Anderson quotes.