1. Carnahan J. (1991). “Life cycle cost analysis for underground heat distribution systems.” Rep. Contract No. DAAL03-86-D-001 U.S. Army Construction Engineering Research Laboratory Champaign Ill.
2. Carnahan J. (1995). “A comparative life cycle cost analysis of underground heat distribution systems.” Rep. Contract No. DACA88-94-M-0674 U.S. Army Construction Engineering Research Laboratory Champaign Ill.
3. Leak Location and Repair Cost for Underground Heat Distribution Systems
4. Cooper K. Marsh C. and Segan E. (1986). “Evaluation of techniques for locating leaks in underground heat distribution systems.” Tech. Rep. M-86/16 U.S. Army Construction Engineering Research Laboratory Champaign Ill.
5. Demetroulis N. (1990). “Inspection of underground heat distribution systems demonstration project.” Summary Rep. NMD & Associates Alexandria Va.