(HTM) Schurz-refs.html
 (GIF) abstr50-69.gif
 (DOC) abstr50-69.pdf
 (TXT) abstr50-69.ps
 (HTM) pp50-69.html
 (DOC) pp50-69.pdf
 (TXT) pp50-69.ps
 (TXT) pp50-69.txt