1. Lab. for Soil and Water Management; Faculty of Agricultural and Applied Biological Sciences; Kasteelpark Arenberg 20 3001 Leuven/Heverlee Belgium
2. Soil Microbiology Unit; International Institute of Tropical Agriculture (IITA); Ibadan Nigeria
3. c/o Lambourn, Carolyn House, 26 Dingwall Road Croydon CR9 3EE UK