Analytical method: UNKNOWN
| Technique | UNKNOWN |
|---|---|
| Material | WHOLE ROCK |
| Mineral | none |
| Institution | Unknown, Unknown, USA |
| Reference | Verma, Surendra P; Lopez, M M (1982) Geochemistry of Los Humeros Caldera, Puebla, Mexico. Bulletin Volcanologique. 45; 1, Pages 63-79. 1982. |