1. Relevance of zinc in human sperm flagella and its relation to motility
Ralf Henkel, Ph.D., Jörg Bittner, M.D., Ralf Weber, Ph.D., Friedrich Hüther, Ph.D., Werner Miska, Ph.D. 
Fertility and Sterility 
Volume 71, Issue 6, Pages (June 1999)
DOI: /S (99)

2. FIGURE 1
Correlation of flagellar zinc content of human spermatozoa with global motility (A) and progressive motility (B). A highly significant negative correlation can be observed (A: r = −.484, P<.001; B: r = −.534, P<.001, n = 90).
Fertility and Sterility  , DOI: ( /S (99) )