Класификација звезда по луминозности — разлика између измена

* {{Cite book | title=Philip's Astronomy Encyclopaedia | editor = Patrick Moore | publisher=Philip's | year=2002 | location=London |language = {{ен}} | isbn=0-540-07863-8| ref = harv}}

* {{Cite book|editor = Ian Ridpath | year = 1998 | title = Oxford Dictionary of Astronomy | publisher = Oxford University Press | location = New York |language = {{ен}} | id = ISBN 0-19-211596-0| ref = harv}}