There are a number of categories of references included in the References Table. These categories are listed below with their tags. SWEREFs are tagged to allow easy access to the members of a category in case there is a need to update some or all members of the category.
|npr||NASA Procedural Requirements|
|npd||NASA Policy Directives|
|llis||Lessons Learned - includes entries in the LLIS database as well as documents that contain Lessons Learned and are referenced in the SWEHB|
|tp||Technical papers, presentations and other non-NASA documents|
|pa||Process Asset, typically from a Center. Some may be found in SPAN.|
|test||SWEREFs reserved for testing|