Grokking Bitcoin http://rosenbaum.se/book/grokking-bitcoin.html
Eric Voskuil - Building on Bitcoin 2018 http://diyhpl.us/wiki/transcripts/building-on-bitcoin/2018/libbitcoin/
James Chiang - Libbitcoin: A practical introduction https://diyhpl.us/wiki/transcripts/scalingbitcoin/tel-aviv-2019/edgedevplusplus/libbitcoin/