Search SEDIS
| Data sets | Publications | Expeditions | Thesaurus | 
| He-4  | |
|---|---|
| BT | isotopes | 
| .stable isotopes | |
| ..He-4 | |
| BT | noble gases | 
| .helium | |
| ..He-4 | |
| RT | He-4/He-3 | 
| SN | This term has multiple hierarchies. | 
| He-4/He-3  | |
|---|---|
| BT | isotopes | 
| .stable isotopes | |
| ..He-4/He-3 | |
| BT | noble gases | 
| .helium | |
| ..He-4/He-3 | |
| UF | He-3/He-4 | 
| RT | absolute age | 
| isotope ratios | |
| He-3 | |
| He-4 | |
| SN | Isotopic ratio. As of 1989, use He/He for age determination method. This term has multiple hierarchies. |