Projects sponsored by these or affiliated agencies are included. Further descriptions can be found from the USDA website . Access is free on the net . Started in 1970, this has become an important database limited only by its bibliographic nature. Further descriptions can be found from OVID FieldGuide , Dialog , SilverPlatter , FirstSearch and from the USDA website .
Access is free on the net .
Further descriptions can be found from their website faq or website . Access is free on the net . The information is factual and numerical - and includes both current and past submissions. Further descriptions can be found from their website here or here . Access is free on the net .