| value | technique | year | title_of_literature<MAX120col.> | journal<MAX120col.> | vol | page | name<MAX80col.> |
| 0.07 | FAA |
1987.07 | Personal communication, UNDP Philippines | | | | I.Rubeska |
| 0.07 | AA |
1987.07 | Personal communication, BMG, Philippines | | | | E.M.Macalalad |
| 0.11 | ICPMS |
1990 | Rapid determination of seven trace elements in rock reference samples by ICP-MS (in Japanese with English abstract) | Bunseki Kagaku | 39 | 55-59 | T.Okai |
| 0.063 | AA |
1991.01 | Personal communication, Geological Survey of Japan | | | | S.Terashima |
| <2 | EXRF |
2002 | Personal Communication, Southern Connecticut State Univ., USA | | | | T. Fleming |