The audio-visual handbook
By: by Ellsworth C. Dent.
Contributors: Society for Visual Education.
Edition: 4th ed.
Publisher: Society for Visual Education
Published: 1946
Place of publication: Chicago
Language: eng
Number of pages: 227
Subjects: Visual education.; Motion pictures in education.; Radio in education.
Notes: First edition, 1934, has title: A handbook of visual instruction.

"Sources of information, materials and equipment": p. 199-227.