An article in Georgia Southern Magazine: http://news.georgiasouthern.edu/magazine/2013/12/12/an-evening-with-laura-bush/

Quoted from article: 

GS [Georgia Southern]: What type of family traditions will you introduce to your granddaughter?

LB [Laura Bush]: “Mila loves to look at books and chew on them, which is mainly what she wants to do! But, it’s fun to read to her, and I am going to continue our family traditions of reading together. One of my favorite memories is when George and I used to read the Hank the Cow Dog books to the girls when they were a little bit older. Those books are hilarious, and they are fun to read aloud.”