Sources

Caricature: From Leonardo to Picasso
By Werner Hofman

Caricatures of the Ancient
Awe Caricature Art
Unlocking the Mysteries of the Artistic

Sources

Here are some of the sources I have found:

The Art of Caricature, by Edward Lucie-Smith

The Art of Satire, by Ralph E. Shikes and Steven Heller

The Dictionary of British Bok Illustrators and Caricaturists 1800-1914, by Simon Houfe

Great Caricatures

Britannica Online Encyclopedia's article "Caricature and Cartoon"

Post-WWI Resources.

Here's a small selection of the various image-heavy links that I have collected for my section of the research. Most of it is post-WWI and spans across the globe.

The National Portrait Gallery's caricature exhibit (American caricatures)
BibliOdyssey's scans of satirical maps
Gallery of anti-US Chinese satirical cartoons
New Yorker slideshow of satirical caricatures and covers
Extensive galleries of caricatures, organized by artist

ELLY: ORIGINS, EARLY WORK
NIKI: TECHNOLOGICAL DEVELOPMENTS
ANNIE: WWI – PRESENT

ALL: ARTISTS, SHIFTS IN TRENDS