The [[liberal]] [[Public Broadcasting Service]] explained the history of '''E=mc²''' for its NOVA series as follows:<ref>http://www.pbs.org/wgbh/nova/physics/ancestors-einstein.html</ref> | The [[liberal]] [[Public Broadcasting Service]] explained the history of '''E=mc²''' for its NOVA series as follows:<ref>http://www.pbs.org/wgbh/nova/physics/ancestors-einstein.html</ref> |