https://magazine.frva.com/2011/01/01/tree-squirrels/
Tree Squirrels - Family RVing Magazine
Jan 1, 2011 - Trusted resource for RV enthusiasts. Learn RV maintenance and how-to tips, plus read RV reviews, news, and product info to enhance the RV lifestyle. Official...
tree squirrelsfamilyrvingmagazine
https://animaldiversity.org/accounts/Sciurinae/classification/
Sciurinae (tree squirrels, flying squirrels, and relatives) | CLASSIFICATION | Animal Diversity Web
tree squirrelsflyingrelativesclassificationanimal
https://www.aginfo.net/report/65192/California-Tree-Nut-Report/Identifying-Ground-Squirrels-in-Tree-Nut-Orchards
Identifying Ground Squirrels in Tree Nut Orchards - AG INFORMATION NETWORK OF THE WEST
Roger Baldwin is a Wildlife Specialist, University of California-Davis. He comments on ground squirrels and their damage to tree nuts.