https://archive.lib.msu.edu/tic/gcman/article/2016[...] | 08/05/2016 | PDF Reader | | Item is within a single large file |
http://web.archive.org/web/20160811144206/http://w[...] | 03/17/2017 | | | |
https://www.greenkeeperverband.at/wp-content/uploa[...] | | PDF Reader | | Item is within a single large file; Greenkeeper News German reprint |