520 books • 20 series
The Bobbsey Twins at Snow Lodge (Bobbsey Twins, #5) (Bibliolife Reproduction Series Bobbsey Twins)
The Bobbsey Twins on Blueberry Island (Bobbsey Twins (Grosset & Dunlap Hardcover), #10)
The Bobbsey Twins' Adventure in Washington (Bobbsey Twins (Grosset & Dunlap Hardcover), #12)