public void setCampus(Campus campus) {
		if (campus != this.campus) {
			Campus vorigeCampus = this.campus;
			this.campus = campus;
			if (vorigeCampus != null && vorigeCampus.getManager() == this) {
				vorigeCampus.setManager(null);
			}
			if (campus != null && campus.getManager() != this) {
				campus.setManager(this);
			}
		}
	}