The New American Standard Bible Study Set is provided through
The Lockman Foundation.

This is not a Public Domain resource, nor is it free. There is a nominal fee associated with these resources, but there is a lot here for the money!

Included in this study set is the NASB, the NASB with Strong's numbers, NAS77, and the NAS Exhaustive Concordance!

These resources are locked and will require you to purchase the security key for $20 from The Lockman Foundation.