Facebook group - specifically set up for owners of Interstate aircraft and Arctic Terns
Mathew Northway's excellent book about flying his Interstate Cadet to OshKosh - Mr. Northway owns one of the prettiest cadets out there and captures his adventures getting to know the airplane on a long cross-country from the Pacific Northwest to Wisconsin and back.
A source for Interstate Cadet logo stickers - these are similar to the ones many cadets have on them
Gerry Casey's book about the early days of aviation - he was a test pilot for some of the early Interstate Aircraft tests and has several excerpts about that time, including flying General Patton around!
Kent Pietch Air Shows - Kent has amazed millions of spectators flying his Interstate Cadet in air shows.
A selection of Interstate parts - Tim Talen has some inventory of various hard-to-find Interstate-specific parts that anyone restoring or working on one of these planes will find very useful. Reach out to him for pricing and availability.