Use the Tripod catalog for your home institution This link opens in a new window This link opens in a new window It includes the print books at the other two colleges that you can request. When searching for books in Tripod use the Books + Media channel.
You can Limit your results to ONLINE in the availability filter in the upper left corner of the results screen.
An important place to look for many materials not owned by the Tricollege Libraries. This combined library catalog contains more than 500 million records for material owned by libraries around the world. Many of these items are available to you though interlibrary loan. Use the button to place requests. Also note that older books, reports and dissertations are often listed with open access URLs.