EDIT

import java.util.List;

import java.util.Set;

import javax.persistence.Entity;

import javax.persistence.FetchType;

import javax.persistence.JoinColumn;

import javax.xml.bind.annotation.XmlType;

import org.apache.log4j.Logger;

import org.hibernate.annotations.Cascade;

import org.hibernate.annotations.CascadeType;

import org.hibernate.envers.Audited;

	@XmlElement(name = "rootNode")

    @XmlIDREF

    @XmlSchemaType(name = "IDREF")

	@OneToMany(fetch=FetchType.LAZY)

    @Cascade({CascadeType.SAVE_UPDATE, CascadeType.MERGE})

	//TODO

	private List<TaxonNode> rootNodes = new ArrayList<TaxonNode>();

	@XmlElement(name = "reference")

	@Override

	public TaxonNode addChildTaxon(Taxon taxon, Reference citation, String microCitation) {

	}

	@Override