l_blue_book_heading: 150, 480, 400
| bb_heading | bb_chapter | bb_division | description |
|---|---|---|---|
| 150 | 480 POSTAL SERVICE UNITS 480 | 400 BARGAINING UNITS 400 | BARGAINING HISTORY AND PRACTICE |
| bb_heading | bb_chapter | bb_division | description |
|---|---|---|---|
| 150 | 480 POSTAL SERVICE UNITS 480 | 400 BARGAINING UNITS 400 | BARGAINING HISTORY AND PRACTICE |