519 books • 20 series
Bobbsey Twins 00: Wonderful Winter Secret (Bobbsey Twins (Grosset & Dunlap Paperback), #24)
Mystery at School (Bobbsey Twins (Grosset & Dunlap Hardcover), #4) (Bobbsey Twins (Grosset & Dunlap Paperback), #4)
Bobbsey Twins 00: Mystery of the Deep Blue Sea (Bobbsey Twins (Grosset & Dunlap Hardcover), #11)