Index: tol/stdlib/general/_constant.tol
===================================================================
--- tol/stdlib/general/_constant.tol	(revision 2bcc6b64e19c876e20fe1c9ccacb23598437dd95)
+++ tol/stdlib/general/_constant.tol	(revision 29f736f68a87ef8ef2ef82dbd2212a6bda3e8b0d)
@@ -70,4 +70,5 @@
 TimeSet Bimestral     = D(1)*(M(1)+M(3)+M(5)+M(7)+M(9)+M(11));
 
+
 //VBR: Se mantiene por compatibilidad hacia atrás pero no es el significado
 //correcto en castellano pues en realidad sería equivalente a Semimensual
@@ -105,4 +106,8 @@
 TimeSet PseudoAnual   = Range(M(1)*D(1),0,6)*WD(1);
 
+TimeSet CtH06b00 = Hourly*(H(0)+H(6)+H(12)+H(18));
+TimeSet CtH06b03 = Hourly*(H(3)+H(9)+H(15)+H(21));
+TimeSet CtH03b00 = Hourly*(H(0)+H(3)+H(6)+H(9)+H(12)+H(15)+H(18)+H(21));
+
 //////////////////////////////////////////////////////////////////////////////
 // Various time series objects frequently used