微软官方N-Tier 介绍:https://docs.microsoft.com/zh-cn/visualstudio/data-tools/n-tier-data-applications-overview
三层架构wiki
https://en.wikipedia.org/wiki/Multitier_architecture#Three-tier_architecture
https://en.wikipedia.org/wiki/Multitier_architecture
四个洋葱架构(Onion Architecture)的原则:
来源: http://www.cnblogs.com/linezero/p/architecture.html