diff --git a/ontology/saref4envi.ttl b/ontology/saref4envi.ttl
index 84946fde0ce41cd8e4c6a2614832931385c6c360..3b01bd73161c3db4c85675d73369083b6ef21ca4 100644
--- a/ontology/saref4envi.ttl
+++ b/ontology/saref4envi.ttl
@@ -844,78 +844,6 @@ saref:UnitOfMeasure rdf:type owl:Class ;
 #    Individuals
 #################################################################
 
-###  http://www.wurvoc.org/vocabularies/om-1.8/centimetre
-<http://www.wurvoc.org/vocabularies/om-1.8/centimetre> rdf:type owl:NamedIndividual ,
-                                                                :LengthUnit ;
-                                                       rdfs:label "Centimetre"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/decametre
-<http://www.wurvoc.org/vocabularies/om-1.8/decametre> rdf:type owl:NamedIndividual ,
-                                                               :LengthUnit ;
-                                                      rdfs:label "Decametre"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/decimetre
-<http://www.wurvoc.org/vocabularies/om-1.8/decimetre> rdf:type owl:NamedIndividual ,
-                                                               :LengthUnit ;
-                                                      rdfs:label "Decimetre"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/hectometre
-<http://www.wurvoc.org/vocabularies/om-1.8/hectometre> rdf:type owl:NamedIndividual ,
-                                                                :LengthUnit ;
-                                                       rdfs:label "Hectometre"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/hertz
-<http://www.wurvoc.org/vocabularies/om-1.8/hertz> rdf:type owl:NamedIndividual ,
-                                                           :FrequencyUnit ;
-                                                  rdfs:label "Hertz"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/kilometre
-<http://www.wurvoc.org/vocabularies/om-1.8/kilometre> rdf:type owl:NamedIndividual ,
-                                                               :LengthUnit ;
-                                                      rdfs:label "Kilometre"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/metre
-<http://www.wurvoc.org/vocabularies/om-1.8/metre> rdf:type owl:NamedIndividual ,
-                                                           :LengthUnit ;
-                                                  rdfs:label "Metre"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/millimetre
-<http://www.wurvoc.org/vocabularies/om-1.8/millimetre> rdf:type owl:NamedIndividual ,
-                                                                :LengthUnit ;
-                                                       rdfs:label "Milimetre"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/reciprocal_day
-<http://www.wurvoc.org/vocabularies/om-1.8/reciprocal_day> rdf:type owl:NamedIndividual ,
-                                                                    :FrequencyUnit ;
-                                                           rdfs:label "Reciprocal day"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/reciprocal_hour
-<http://www.wurvoc.org/vocabularies/om-1.8/reciprocal_hour> rdf:type owl:NamedIndividual ,
-                                                                     :FrequencyUnit ;
-                                                            rdfs:label "Reciprocal hour"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/reciprocal_second-time
-<http://www.wurvoc.org/vocabularies/om-1.8/reciprocal_second-time> rdf:type owl:NamedIndividual ,
-                                                                            :FrequencyUnit ;
-                                                                   rdfs:label "Reciprocal second"@en .
-
-
-###  http://www.wurvoc.org/vocabularies/om-1.8/reciprocal_year
-<http://www.wurvoc.org/vocabularies/om-1.8/reciprocal_year> rdf:type owl:NamedIndividual ,
-                                                                     :FrequencyUnit ;
-                                                            rdfs:label "Reciprocal year"@en .
-
-
 ###  https://saref.etsi.org/saref4envi/Fluorescence
 :Fluorescence rdf:type owl:NamedIndividual ,
                        :LightProperty ;