RPKI chain of trust

Good morning everyone, I have a doubt about RPKI chain of trust. The 5 RIRs hold a self-signed root certificate for all the resources they have in the registry. The root certificate is used to sign the LIR's certificates that lists LIR's resources. LIRs use their private key to sign ROAs. LIR's public key is used to verify ROAs signatures and RIRs public key is used to verify LIR's signatures. Is this correct? Thanks in advance, Fabiano