Xiu's writings are vital materials for the study and research of Tongbeiquan.

The reason given had to do with a shortage of vital materials.

The structural weaknesses could delay production of vital material well into 1990.

"And add shovels to that list of vital materials."

He also discovers vital materials to help Sphinx save the mayor from his illness.

It has lost the capacity to make tritium, a vital nuclear material.

However, these sanctions did not extend to several vital materials, such as oil, and were not carried out by all members of the League.

Lack of vital materials will eventually lead Montenegro to surrender.

However, these sanctions did not extend to several vital materials, such as oil.

The shortage of tritium, a vital material for nuclear weapons, arrived right on schedule.