Documents regarding communication with submarines in the ELF range

Documents regarding communication with submarines in the ELF range:

http://www.virhistory.com/navy/commsta/elf/elf-463-22A.pdf

https://fas.org/nuke/guide/usa/c3i/fs_clam_lake_elf2003.pdf

https://www.hep.wisc.edu/~prepost/ELF.pdf

http://www.virhistory.com/navy/commsta/elf/elf-info-8202.pdf

https://books.google.pl/books?id=IAEAAAAAMBAJ&lpg=PP1&dq=Apr+1987&pg=PA46&redir_esc=y#v=onepage&q&f=false

http://blackradios.terryo.org/documents/publications/e-ELF.pdf

https://books.google.pl/books?id=NOPpwVvNu44C&pg=PA39&redir_esc=y#v=onepage&q&f=false

http://www.plrc.org/docs/941005B.pdf

https://www.nytimes.com/1981/10/13/science/how-huge-antenna-can-broadcast-into-the-silence-of-the-sea.html?pagewanted=all