PREFIX mo:       <http://purl.org/ontology/mo/>
PREFIX dc:  <http://purl.org/dc/terms/>
PREFIX mu: <http://purl.org/NET/c4dm/music.owl#>
PREFIC event: <http://purl.org/NET/c4dm/event.owl#>

SELECT ?instrument
WHERE
{
	?signal mo:publishedAs <http://mm.music.org/track/5fb524f1-8cc8-4c04-a921-e34c0a911ea7>.
	?performance event:hasProduct ?sound.
	?recording event:hasFactor ?sound;
		event:hasProduct ?signal.
	{
		?performance event:hasFactor ?instrument.
		?instrument a mu:Instrument.
	}
	UNION
	{
		?performance event:hasSubEvent ?subperformance.
		?subperformance event:hasFactor ?instrument.
		?instrument a mu:Instrument.
	}
}