1. Kidder GW, Dewey VC (1949) J Biol Chem 179: 181
2. Woolley DW, Shaw E (1951) J Biol Chem 189: 401
3. Lister JH,Manners DS,Timmis GM (1970) J Chem Soc 1313
4. Labouta IM, Soliman FSG, Kassem MG (1986). Pharmazie 41: 812
5. Ibrahim EA, Shams El Dine SA, Soliman FSG, Labouta IM (1978) Z Naturforsch 33 b: 1503