http://www.whatispiping.com/underground-piping-stress-analysis
http://www.whatispiping.com/restrained-and-unrestrained1
http://www.whatispiping.com/restrained-and-unrestrained2
http://www.whatispiping.com/virtual-anchor-length-calculation-for-pipelines
http://www.whatispiping.com/what-if-piping-continuation-is-unknown-part-2-underground-piping
http://www.whatispiping.com/various-analysis-methods-for-underground-piping-using-caesar-ii
https://www.passuite.com/kbase/doc/start/WebHelp_en/index.htm#t=elemustbeskanaln.htm
http://www.iwtc.info/2007_pdf/7-5.pdf
https://rules.dnvgl.com/docs/pdf/DNV/codes/docs/2011-11/RP-F109.pdf
https://www.witpress.com/Secure/elibrary/papers/RISK04/RISK04013FU.pdf
https://www.collectionscanada.gc.ca/obj/s4/f2/dsk3/OKQ/TC-OKQ-737.pdf
https://brage.bibsys.no/xmlui/bitstream/handle/11250/274140/ghebreghiorghis_dawit.pdf?sequence=1
https://www.steeltank.com/Portals/0/pubs/SPED_VL3.pdf
http://onlinepubs.trb.org/Onlinepubs/trr/1988/1191/1191-007.pdf