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AIR. (General Science)
…Arranged and produced by Gerrit C. Zwart; drawings, Helen S. Zwart. Gerrit C. Zwart d.b…
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1937 |
Visual Sciences |
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ENERGY. (General Science)
…Visual Sciences (Gerrit C. Zwart, author); 1Nov37; MP8041.
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1937 |
Visual Sciences |
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FIRE AND HEAT. (General Science)
…Arranged and produced by Gerrit C. Zwart; from drawings by Helen S. Zwart. Gerrit C. Zwart…
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1937 |
Visual Sciences |
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FUNDAMENTALS OF BIOLOGY Visual Sciences.
…Johnson; drawings & letterings by Helen Smith Zwart. © Gerrit C. Zwart d.b.a. Visual Sciences; 10Nov69…
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1969 |
Gerrit C. Zwart d.b.a. Visual Sciences |
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HISTORY OF DEVELOPMENT OF ENERGY.
HISTORY OF DEVELOPMENT OF ENERGY. 1936. Filmstrip, 24 frames. Gerrit C. Zwart; 10May36; MP6659.
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1936 |
Gerrit C. Zwart |
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LIGHT. (General Science)
…Visual Sciences (Gerrit C. Zwart, author); 15Nov37; MP8040.
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1937 |
Visual Sciences |
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MECHANICS (General Science, no. 1)
…Visual Sciences (Gerrit C. Zwart, author); 15Nov37; MP8039.
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1937 |
Visual Sciences |
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OPTICAL ILLUSIONS.
…Visual Sciences (Gerrit C. Zwart, author); 22Jan37; MP7346.
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1937 |
Visual Sciences |
1 reel |
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Optical Illusions. Pt. 2
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1966 |
Visual Sciences |
34 fr |
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PRINCIPLES OF CHEMISTRY.
PRINCIPLES OF CHEMISTRY. 1934. 1 reel. Gerrit C. Zwart (Gerrit Carl Zwart, author); 2Apr34; MP4721.
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1934 |
Gerrit C. Zwart (Gerrit Carl Zwart author) |
1 reel |
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PRINCIPLES OF PHYSICS.
PRINCIPLES OF PHYSICS. 1932. 1 reel. Credits: Producer, Gerrit C. Zwart. Gerrit Carl Zwart; 1Jun32; MP3711.
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1932 |
Gerrit Carl Zwart |
1 reel |
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WATER. (General Science)
…Arranged and produced by Gerrit C. Zwart; drawings by Helen S. Zwart. Gerrit C. Zwart d…
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1937 |
Visual Sciences |
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