B:
Bridges - Science Tracer Bullet - Bridges - Science Tracer Bullets - Research Finding Aids from the Library of Congress, Science Reference Services. [U.S. Library of Congress (LOC)]

M:
Mapping the Moon with WALL·E - Webcast - Mapping the Moon with WALL·E - Marci Delaney, PhD., NASA, at at talk at the Library of Congress, shows how NASA and WALL-E partner to help students across the country learn how scientists and engineers work together to accomplish robotic missions. [U.S. Library of Congress (LOC)]

R:
Record Group 198: Records of the Board of Investigation and Research-Transportation, 1940 - 1944 - National Archives' Archival Research Catalog description for Record Group 198: Records of the Board of Investigation and Research-Transportation, 1940 - 1944 [U.S. National Archives and Records Administration (NARA)]

Record Group 298: Records of the Office of Naval Research, 1941 - 1970 - National Archives' Archival Research Catalog description for Record Group 298: Records of the Office of Naval Research, 1941 - 1970 [U.S. National Archives and Records Administration (NARA)]

U:
US DOT Research Hub - A searchable database of the latest USDOT-sponsored research, development and technology projects. [U.S. Department of Transportation (DOT)]