Common Sense Home - This 1980s popular mechanics article is pretty popular in the root cellar, prepping and food storage groups. Found a free pretty good reference old Popular Mechanics for building
Small-Scale Postharvest Handling Practices
Build a Root Cellar on Your Farm - AGCO FarmLife
Basement root cellar build w/ pics (root-cellars forum at permies)
Root cellar with ventilation shaft Stock Photo - Alamy
DIY Root Cellars 101 - How To Build and Use a Root Cellar