Lightning Test Network Topology
https://medium.com/@murchandamus/a-look-at-an-early-ln-testnet-topology-a874a6ff41d9

The Lightning Network Explained, Part I: How to Build a Payment Channel
https://btcmanager.com/lightning-network-primer-pt-i-building-payment-channels/

Understanding the Lightning Network, Part 1: Building a Bidirectional Bitcoin Payment Channel
https://bitcoinmagazine.com/articles/understanding-the-lightning-network-part-building-a-bidirectional-payment-channel-1464710791/

The Bitcoin Lightning Network:
Scalable Off-Chain Instant Payments

https://lightning.network/lightning-network-paper.pdf