@misc{indiciae23785ac8238c,
  title = {Long-period events, the most characteristic seismicity accompanying the emplacement and extrusion of a lava dome in Galeras Volcano, Colombia, in 1991},
  author = {Cruz F. Gil and B. A. Chouet},
  year = {1997},
  url = {https://pubs.usgs.gov/publication/70019754},
  note = {Source identifier: 70019754}
}