• 7 Videos, Slides, Films

• 1 DVDs

• 7 History
• 7 Technological innovations
• 7 Technology
• 6 Documentary films
• 1 Air conditioning
• 1 Electric lighting
• 1 Glass
• 1 Inventions
• 1 Inventors
• 1 Public health
• 1 Recording and reproducing
• 1 Refrigeration and refrigerating machinery
• 1 Sanitary engineering
• 1 Sound
• 1 Time measurements

• 7 Johnson, Steven, 1968-
• 6 Kanopy (Firm)
• 4 Jones, Julian
• 3 Olding, Paul, 1973-
• 2 Stacey, Nic
• 1 British Broadcasting Corporation
• 1 Jackson, Michael, 1958 February 11-
• 1 Nutopia (Firm)
• 1 Oregon Public Broadcasting
• 1 PBS Distribution (Firm)
• 1 Petterle, Diene
• 1 Public Broadcasting Service (U.S.)
• 1 Root, Jane

• 7 English

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