1. W. Coffin and R. Alward, Design and testing of a cold climate greenhouse. INTERSOL 85 Proceedings, Montreal, Canada (1985).
2. Heat transfer characteristics of plastic corrugated drainage tubes buried in the soil;Coffin;Solr Energy,1985
3. A design method for underground heat storage systems consisting of shallow horizontal air ducts;Coffin;Solar Energy,1985
4. Design guide for underground heat storage;Lawand,1985