English language
Published Jan. 1, 1959 by McDowell, Obolensky.

Leo Lionni: Little blue and little yellow (1959, McDowell, Obolensky)
English language
Published Jan. 1, 1959 by McDowell, Obolensky.
A little blue spot and a little yellow spot are best friends, and when they hug each other they become green.