I've come across a couple of kids books recently that have boxer dogs in, our 3 year old is really into his books just now.
Keeper by Gerald Durrell
"Gerald Durrell's first book for young children, telling the story of one of his favourite dogs, Keeper - so called because he took it upon himself to look after all the other animals in Durrell's zoo in Jersey."
Happy Tails Earl & Pearl on the Farm by Cindy & Kirby Pringle
"An ABC alphabet book with Boxer dogs in clothes fun"
Pear in a headscarf really makes my chuckle