Numbers, Numbers

I occasionally have idle thoughts. And today's idle thought was 'I wonder if I can think of an author's name of every length from 1 to 20 letters.' Using the names under which they published, this is what I've come up with... fancy having a go? Can you fill in my gaps?

1. Q
2.
3.
4. Saki
5. Ouida
6. Sapper
7. A. A. Milne
8. E. F. Benson
9. Roald Dahl
10. Enid Blyton
11. E. M. Delafield
12. Lewis Carroll
13. Frances Burney
14. Charles Dickens
15. Richmal Crompton
16. Arthur Conan Doyle
17. Ivy Compton-Burnett
18. William Shakespeare
19.
20. Sylvia Townsend Warner


Well, that was worthwhile, wasn't? Happy Monday!