@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix owl: <http://www.w3.org/2002/07/owl#>.
@prefix : <foo://bla#> .

# :foo a :xxx.

:cl owl:equivalentClass
  [a owl:Restriction ;
   owl:onProperty :prop;
   owl:allValuesFrom :xxx ] .

:xxx a owl:Class.

:x a :cl ;  :prop :bla.