Minecraft wiki entry for Door-based_iron_golem_farming, associated text: 1 Overview
2 General requirements
3 Video
4 Iron golem farm designs
4.1 Easy 2-tier build
4.2 Survival mode build: Iron golem village
4.3 4 spawn modules 2-level
4.4 Simpler JL2579 design
4.5 The Iron Stream
4.6 The Iron Head, a 100% Efficient Iron Farm
4.7 Comet 107's 30 Village Iron Farm
4.8 The Iron Casster
4.9 Comet 107's Double Stacking 168 Village Iron Farm
4.10 The Iron Bakery
4.11 Iron Processing Unit (IPU-128)
4.12 Iron Nucleus
4.13 Flexible design
4.14 The Iron Paradise
4.15 Tower design