Owl abstract syntax, equivalent classes

With reference to:
   http://www.w3.org/TR/owl-semantics/syntax.html#2.3.2.1

I see:
[[
axiom ::= 'DisjointClasses(' description description { description } ')'
         | 'EquivalentClasses(' description { description } ')'
         | 'SubClassOf(' description description ')'
]]

which appears to admit "EquivalentClasses( description )" as a valid axiom.

Is this correct?  If so, what does it mean?  I'm guessing there's a missing 
"description" in the EquivalentClasses production.  (Assuming this is so, I 
see no cause to raise a formal comment.)

#g


-------------------
Graham Klyne
<GK@NineByNine.org>
PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E