Willems, Mo. ; My Friend is Sad / Mo Willems. - U. S. A: Scholastic, [c2007] - 57 p. illus. 19.05 cm. ISBN: 9780545071475 Subjects--Topical Terms: English Literature--Friendship--Emotions--SadnessU.S.A--English Story Dewey Class. No.: 813.6 / WIM