VHF Digital Voice
http://www.wx4qz.net/Mode_Overview.pdf
https://www.hamdigitaal.nl/?wpfb_dl=194
http://www.kk4ib.org/digital-voice-modes%20compared.pdf
https://sites.google.com/site/ki4fvi/
http://georgia900p25.hopto.org:61001/w4noc-ki4fvi-MixedModeNetwork.pdf
http://ki4fvi.hopto.org:17000/supermon/link.php?nodes=535865
http://ki4fvi.hopto.org:17000/cgi-bin/lsnodes_web?node=535865