de Groot 1953
Thanks to Google for scanning this pioneering and widely-cited study. Since this study is monumentally important to understanding honey bee nutritional requirements, I’ve unsuccessfully attempted to track down any copyright holder for permission to share it. But as I understand copyright law, since this reprint does not contain any indication of this pre-1978 publication being copyrighted, I believe that it is permissible for me to post it for noncommercial educational purposes. If there is indeed a copyright holder, please notify me and I will immediately take it down.
Download it here.
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