1. D. Felscher and K. Lehmann, GDR Pat. 237223, 1986.
2. D. Felscher and K. Lehmann, GDR Pat. 256196, 1988.
3. Superabsorbent polymers—Media for the enzymatic detection of ethyl alcohol in urine
4. A. Oonishi, M. Kamiyama and K. Okaniva, Jpn. Pat. 02109998, 1990.