It allows adding a prefix to each external document

Supplementary materials can be additional figures, tables, or other materials not included in the main manuscript. Next, we have to let the package know in which external document to look for labels. Also, when the external document changes, both documents have to be re-processed.
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Josephina:
It has been a couple months since I first got them.
(14 September 2016)

Josephina:
Would it be sweet to let them know?
(14 September 2016)

Josephina:
Should I let them know I still have these flowers?
(14 September 2016)

Josephina:
And I've kept them alive for a while, even though I thought I didn't have a green thumb.
(14 September 2016)

Josephina:
So I love these flowers a friend grew from me.
(14 September 2016)

Julene:
How can I calm my friend down?
(14 September 2016)

Julene:
His partner didn't mind if I slept here with him he said he'll sleep on the couch tonight he'll let me stay here with him.
(14 September 2016)

Julene:
He said he wants me to stay and sleep with him tonight.
(14 September 2016)

Julene:
I went into his room and hugged him that's all I can think of.
(14 September 2016)

Julene:
He woke up screaming and crying his eyes out.
(14 September 2016)