http://edepot.wur.nl/16065 | 06/10/2014 | PDF Reader | | Dutch language version |
http://content.yudu.com/Library/A1o6lh/PitchcareJu[...] | 06/11/2014 | PDF Reader | | Pitchcare reprint |
https://stri.lib.msu.edu/itb/articles/233-28.pdf | 07/02/2007 | PDF Reader | | Available to TGIF and STRI users |