;--------------------------- timePeriodOfContent ------------------------------
<preguntas_timePeriodOfContent> -> (
   <pregunta_timePeriod> 
) 
<pregunta_timePeriod> -> (
   How current are the maps)
<infs_timePeriodOfContent> -> (
   <inf_timePeriod>
)
<inf_timePeriod> -> (
   ((?(with the period of time) | ?(with the range of dates varying))
      from ?(the date) <fecha> to ?(the date) <fecha>) |
   (with the begin date <fecha> and the end date <fecha>)
)
<atributos_inf_timePeriodOfContent> -> (
   nil
)
<atributos_pregunta_timePeriodOfContent> -> (
   (?the time period | period of time)
)