U.S. Dept. of Health, Education, and Welfare, Education Division, National Center for Education Statistics : for sale by the Supt. of Docs., U.S. Govt. Print. Off.1975.<FD25-230>
National Diet Library
Author HeadingWestervelt, Esther Manning. Ekstrom, Ruth B.
Esther Manning Westervelt ; (from an original draft by Ruth B. Ekstrom, now expanded, updated, and extensively revised)U.S. Dept. of Health, Education, and Welfare, Education Division, National Center for Education Statistics : for sale by the Supt. of Docs., U.S. Govt. Print. Off.1975