1 INTRODUCTION

2 DATA  
2.1 Target Selection  
2.2 Observations  
2.3 Data Reduction  
2.4 Redshift Measurement  
2.5 Completeness of the Spectroscopic Redshifts

3 GALAXY GROUP IDENTIFICATION  
3.1 Group Identification  
3.2 Caveats

4 ENVIRONMENT AND LINE OF SIGHT CHARACTERISTICS  
4.1 Nearby Galaxies  
4.2 Groups: Overview  
4.3 Groups: Discussion

5 CONTRIBUTION OF LINE OF SIGHT AND ENVIRONMENT TO THE LENS STRUCTURE  
5.1 Individual Galaxies  
5.2 Flexion from Groups

6 CONCLUSION