Its rarity also serve as an invaluable educational resource for everybody.

His writings have proved an invaluable resources for medieval and military historians.

This has proven to be an invaluable resource and one I encourage you to pursue.

For many sales and business professionals, it would be an invaluable resource on a portable computer.

At a time like this, they can be an invaluable resource.

Read on to find out why they're an invaluable resource for both employers and employees.

Jordan was an invaluable resource that she consulted on many occasions.

Also seniors, who have a little more time to spend, can be an invaluable resource.

Just as on the Moon, ice is an invaluable resource for humans and their machines.

By the second book, she had become an invaluable resource and aid in helping me fabricate a world.