How-to: Set-up a site-to-site IPSec connection from a Ubiquiti EdgeRouter behind NAT to Cisco ASA | Sebastiaan Dammann
IPSec VPN Configuration Guide for Cisco ASA 55xx | Zscaler
Site-to-Site IPSEC VPN between Two Cisco ASA 5520 – Router Switch Blog
Configurations on Cisco ASA/FTD device
Site-to-Site IKEv2 IPSec VPN using Pre-Shared Key Authentication - simple configuration example for two Cisco routers - NIL - Network Information Library