To be happy is only to have freed one's soul from the unrest of unhappiness.

The more personal you are, the more universal you become.

The only limit to our realization of tomorrow is our doubts of today.

"A book is a mirror: if a fool looks in, no sage can look out."

We must balance short-term profitability with long-term environmental responsibility.

没有一个明智的飞行员会忘记使用他的清单，无论他的才能和经验有多么出色。

数学的本质不是使简单的事情复杂化，而是使复杂的事情简单化。