W.J. King: "Persistence (tenacity), which is the disposition to persevere in spite of the difficulties, discouragement, or indifference. This last quality is sometimes lacking in the make-up of brilliant engineers, to such an extent that their effectiveness is greatly reduced. Such dilettantes are known as 'good starters but poor finishers.'"

William Swanson: "Persistence or tenacity is the disposition to persevere in spite of difficulties, discouragement, or indifference. Don't be known as a good starter but a poor finisher!"