That's (Not) Mine by Anna Kang illustrated by Christopher Weyant*

This husband-wife team has created another wonderful book for beginning readers.  Their first book You Are (Not) Small won the Theodor Seuss Geisel Award in 2015.
The same two bears are in this story and find themselves arguing over a comfy chair.
This team has captured younger children's frustration over sharing and also their ability to forgive and be friends again very well.
*Highly recommend.
Borrowed from the library.
My kindergartner was eager to read this book aloud to me!
I would highly recommend this book for preschool rooms and K-1st grade rooms.
Strategy: fluency  Perfect for a Reader's Theater for two people.