Reliable direct quotations by Umetaro Suzuki are difficult to verify in primary sources.

-- Umetaro Suzuki

Reliable direct quotations by George Washington Carver are difficult to verify in primary sources.

-- George Washington Carver

Reliable direct quotations by Louis Braille are difficult to verify in primary sources.

-- Louis Braille

No direct personal quotations by Hero of Alexandria survive in the historical record.

-- Hero of Alexandria

In ancient times, writings were generally inscribed on bamboo strips; those using silk cloth were called 'paper.' Silk was expensive and bamboo heavy — neither was convenient. Cai Lun then conceived the idea of making paper from tree bark, hemp waste, old cloth, and fishnets.

-- Cai Lun

Reliable direct quotations by Gottlieb Daimler are difficult to verify in primary sources.

-- Gottlieb Daimler