 |
| |||
| primary sources (Published and unpublished records without secondary interpretation or commentary) | |||
| original sources; primary literature | |||
| |||
| primary radiator | |||
| aerial feed; antenna feed | |||
|
sources primaires : 8 a las frases, 4 temas |
| Ciencias de la tierra | 2 |
| Comunicaciones | 3 |
| Finanzas | 1 |
| Industria energetica | 2 |