</p>
<pre class="grammar">
|   alternation
()  grouping
[]  option (0 or 1 times)
{}  repetition (0 to n times)
</pre>

<p>
Lower-case production names are used to identify lexical tokens.
Non-terminals are in CamelCase. Lexical tokens are enclosed in
double quotes <code>""</code> or back quotes <code>``</code>.
</p>

<p>
The form <code>a … b</code> represents the set of characters from

madrid.museum
mallorca.museum
manchester.museum
mansion.museum
mansions.museum
manx.museum
marburg.museum
maritime.museum
maritimo.museum
maryland.museum
marylhurst.museum
media.museum
medical.museum
medizinhistorisches.museum
meeres.museum
memorial.museum
mesaverde.museum
michigan.museum
midatlantic.museum
military.museum
mill.museum
miners.museum
mining.museum