TY  - RPRT
TI  - The international seismological observing period in Africa
AU  - E.R. Engdahl
AU  - Eric A. Bergman
PY  - 1992
DO  - 10.1016/0040-1951(92)90003-o
UR  - https://pubs.usgs.gov/publication/70017152
ID  - 70017152
ER  -