10 Terrifyingly Huge Rodents – look at #4 (Josephoartigasia) and #6 (the modern capybara)
Capybara: Biology, use and conservation of an exceptional neotropical species – this is a PDF of an entire book. Isolated chapters will be of use, particularly #1, #2. Enjoy any you find interesting
Giant fossil rodent had an awesome bite – from National Geographic. Specimen of Josephoartigasia from Uruguay.
Capybara fact sheet – modern capybara information; also see chapters in Capybara: Biology, use and conservation…