The systems used today all developed in the latter half of the 19th century.

Their work in the 1960s and 1970s on how the visual system developed.

The systems developed will link economic, social and environmental data.

Early on December 21, the system developed into a depression.

The discussion was about how the system will develop in the future.

It is generally considered to be one of the most advanced and successful large computer systems ever developed.

Basically, the whole system developed in the same period of time.

Writing systems develop and change based on the needs of the people who use them.

Over the next couple of days the system gradually developed further while moving towards the west.

The educational systems of the Western nations developed international standards.