SPARQL selecting unittext (blank nodes) - sparql

Question

I recently started working with Linked Data and SPARQL.
I've a dataset which contains unittext, indicating what kind of unit the property has (meters, kilograms and so on).
The unit is a values which is inserted on the relationship between object and its quantitative property.
In my RDF dataset the units are included in a blank node and indicated by https://schema.org/unitText.
An example of the data set is included below.
], [
a owl:Restriction ;
owl:minCardinality "0"^^xsd:nonNegativeInteger ;
owl:onProperty <https://someuri> ;
ns1:unitText "kg"
How can I select this property?
The query so far is:
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX sh: <http://www.w3.org/ns/shacl#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
select distinct ?label ?aspect ?datatype where {
?s rdfs:subClassOf/owl:onProperty ?aspect .
?aspect rdf:type owl:ObjectProperty.
?aspect skos:prefLabel ?label .
?aspect rdfs:range ?datatype .
FILTER EXISTS{ ?aspect rdfs:range ?datatype. }
VALUES ?datatype {
xsd:string
xsd:gYear
xsd:boolean
xsd:decimal
xsd:integer
xsd:date
}
}
The RDF dataset looks actually like this:
rdfs:subClassOf [ a owl:Restriction ;
owl:minCardinality "0"^^xsd:nonNegativeInteger ;
owl:onProperty <someuri> ;
<https://schema.org/unitText> "kg"
] ;