The book by James M. Blower and Robert S. Korach is THE book to have. Jim Blower also published a supplement to this book titled "Northern Ohio Traction Revisited". He had more information on the line than could fit into the CERA Publication. This book is about a 180 page soft cover book. A third publication with info on the line is "New Northern Ohio's Interurbans" by Harry Christiansen, published in 1983. This book comes soft and hard cover and has several chapters on the line. It also covers all of the interurban lines in northeastern Ohio.
The 1960's vintage books usually retail in the $70.00 range while the Christiansen book goes for about $20 to $30 depending on binding. Last I knew the museum store at Northern Ohio Railway Museum had the books in stock and for sale. web address is: www.northernohio.railway.museum
The Museum also has the only surviving passenger interurban cars from the Northern Ohio Interurban. Formal public tours have stopped for the season, but you are welcome to stop by the museum and a volunteer will show you around. This time of year I can't guarantee when staff will be there. Public tours resume in May on Saturdays. Check the web site for hours and start date.
Northern Ohio Railway Museum