The Tannin Handbook is a collection of methods used in the Hagerman Tannin lab at Miami University for purification, structure determination, and assessment of bioactivity. The methods are generally written as "recipes" that can be followed directly. Each method has one or more literature citations that provide the original published methods. I strongly recommend that you refer to the original articles since they generally provide in depth information that is essential for choosing the correct method for your application, and for analyzing the data.
In general, I recommend that you use and cite the original literature. If you need to cite the Tannin Handbook, you may use the following information:
Hagerman, A.E. 2002. Tannin Handbook. Miami University, Oxford OH 45056 www.users.muohio.edu/hagermae/