1. Dep. of Environ. Sci. and Eng., Oregon Grad. Inst. of Sci. and Technol. 19600 N.W. Von Neumann Dr. Beaverton OR 97006‐1999;
2. Dep. of Vegetable Crops Univ. of California Davis CA 95616
3. Dep. of Land, Air and Water Resour. Univ. of California Davis CA 95616