try {
			Context.getLogicService().getLogicDataSource("obs").getKeys().add("LAST RETURN VISIT DATE");
			Context.getLogicService().addRule("RETURN VISIT DATE", new ReferenceRule("obs.LAST RETURN VISIT DATE"));
		} catch (InvalidReferenceRuleException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		} catch (LogicException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}

		nextWeeksAppointments.addLogicColumn(new LogicDataSetColumn("RETURN VISIT DATE", Date.class, "RETURN VISIT DATE"));