1. General pipeline FAQs, http://phmsa.dot.gov/about/faq; 2013.
2. PHMSA update: aging infrastructure and integrity verification process;Nanney,2013
3. PHMSA response letter: general pipeline FAQs, http://phmsa.dot.gov/about/faq; 1970.
4. Integrity characteristics of vintage pipelines;Leis,2004
5. Failures of pipelines;Kiefner,1986