1. ; Organic Chemistry; Allyn & Bacon Inc.: Boston, 1987; p 1251.
2. In Wood Adhesives: Chemistry and Technology; Ed.; Marcel Dekker: New York, 1983; p 105.
3. Formaldehyde, 3rd ed.; Robert E. Keieger Publishing Co.: Malabar, FL, 1964; p 486.
4. Characterizations of Phenol-Formaldehyde Resol Resins