1. (1) World LP Gas Association, Automotive LP Gas ─ Today's Fuel For a Cleaner Tomorrow, 3rd Edition, (1998).
2. (2) Kang, K., Lee, D., Oh, S. and Kim, C., Performance of a Liquid Phase LPG Injection Engine for Heavy Duty Vehicles, SAE Paper No.2001-01-1958, (2001).
3. (3) Goto, S., Lee, D., Shakal, J., Harayama, N., Honjyo, F. and Ueno, H., Performance and Emissions of LPG Lean Burn Engines for Heavy Duty Vehicles, SAE Paper No.1999-01-1513, (1999).
4. (4) Gomes, A. and Reinke, P., Lean Burn: A Review of Incentives, Methods, and Tradeoffs, SAE Paper No.880291, (1988).
5. (5) Weide, J.V.D., Seppen, J.J., Ling, J.A.N.V. and Dekker, H.J., Experiences with CNG and LNG Operated Heavy Duty Vehicles with Emphasis on US HD Diesel Emission Standards, SAE Paper No.881657, (1988).