I am trying to quantify a highly transcribed RNA to normalize transcription and I thought about ribosomal RNAs (rRNAs).

I thought that 18S-28S rRNA should work, but what ID exactly?

Candidates: 18S ribosomal RNA AT2G01010    

versus:    rrn18 Gene description 18S ribosomal RNA  (I think the last one is mitochondrial, am I right?).

Would it make sense to measure also 25S rRNA? They apparently are transcribed in tandem.

¿Another highly expressed RNA to consider as a possibility?

References welcomed!

Thank you!