The European and Mediterranean Plant Protection Organization (EPPO) has recently updated its standard that describes the production of certified pathogen-tested olive trees and rootstocks. You can find it here:
https://doi.org/10.1111/epp.12883.
The IOC considers this standard of fundamental importance and endorses the EPPO scheme to reinforce and widely disseminate recommendations for the nursery industry in the olive plant-producing countries of the world.