I recently purchased the book "Creating Animal Sculptures Using Paper Mache Clay" by this same artist and it is very useful! You can achieve a great amount of detail using this form of paper mache clay.
Gumby Imagined, The Story of Art Clokey and His Creations
The ultimate Gumby retrospective packed with incredible photos and never-before-shared stories. Written by Art Clokey's children, Joan and Joe Clokey, this is the most comprehensive book ever published on Gumby, Davey and Goliath and their creator Art Clokey, a pioneer in stop-motion animation.