1. Supelco Technical Bulletin #T197910, Supelco Inc., Bellefonte, PA.
2. J.T. Baker Technical Bulletin, Solid Phase Extraction for Sample Preparation, Phillipsburg, NJ USA.
3. Varian Technical Bulletin, Solid Phase Extraction, Varian, Harbor City, PA.
4. The Handbook of Sorbent Extraction Technology,1993
5. Solid Phase Extraction;Thurman,1998