1. Cantarella, H. and de Abreu, M.(2004) Evaluation of the performance of laboratories in 2003. In 19th Annual Meeting of IAC Soil Proficiency Testing Program for Laboratories of Soil Analysis. . Campinas : Instituto Agronomico. (in Portuguese)
2. Cantarella, H. and van Raij, B. and Quaggio, J. (1998) Soil and plant analysis for lime and fertilizer recommendations in Brazil Communications in Soil Science and Plant Analysis, 29, pp. 1691 - 1706.
3. Cools, N. and Delanote, V. and Scheldeman, X. and Quataert, P. and de Vos, B. and Roskams, P. (2004) Quality assurance and quality control in forest soil analyses: A comparison between European soil laboratories Accreditation and Quality Assurance, 9, pp. 688 - 694.
4. Klesta, E. and Bartz, J.(1996) Quality assurance and quality control. In Methods of Soil Analysis, Part 3: Chemical Methods. ( pp. 18 - 48 ). Madison Wisconsin: Soil Science Society of America.
5. Peck, T. and Soltanpour, P.(1990) The principles of soil testing. In Soil Testing and Plant Analysis3rd ed.. ( pp. 1 - 9 ). Madison Wisconsin: Soil Science Society of America.