| | Web. 21 Feb. 2011. <http://www.slideshare.net/joliver311/Past-Projects- |
| | 1131385>. |
| | |
| | "Seismograph." LEO - Lehigh Earth Observatory. Web. 21 Feb. 2011. |
| | <http://www.leo.lehigh.edu/projects/seismic/seismograph.html>. |
| | |
| | Spence, William P. Insulating, Sealing & Ventilating Your House. New York, |
| | NY: Sterling Pub., 2006. Print. |
| | |
| | Thumma, Stephan. Personal interview. 4 Jan. 2011. |
| | |
| | "What Is a Seismograph?" The Tech Museum | Welcome. Web. 21 Feb. |
| | 2011. <http://www.thetech.org/exhibits_events/online/quakes/seismo/>. |