Input: What order do the flowers in the attic books go?
Output: 

 What order do the flowers in the attic books go including the spin-offs? 
 Flowers in the Attic, Petals on the Wind, If There Be Thorns, Seeds of Yesterday, Garden of Shadows, Christopher's Diary: Secrets of Foxworth, Christopher's Diary: Echoes of Dollanganger and Christopher's Diary: Secret Brother