code: public Expression<Calendar> between(Calendar startValue, Calendar endValue) {
  		String valueString = "'" + getCalendarAsString(startValue).concat("Z") + "' AND '" + getCalendarAsString(endValue) + "'";
  		return new Expression<Calendar>(this, Operation.between, valueString);
  	}
docs: Method to construct the between expression for calendar
  
  @param startValue the start value
  @param endValue the end value
  @return Expression