For those interested in the REU project involving Selmer groups, section 3.5 of Silverman-Tate is the most important section to understand. -kevin -- Kevin James Associate Professor O-21 Martin Hall Department of Mathematical Sciences Clemson University BOX 340975 Clemson, SC 29634-0975 phone: (864) 656-6766 fax: (864) 656-5230 web: www.math.clemson.edu/~kevja/