Answer: endnote

AnswerCrossword Clue
ENDNOTE

Citation at the back

ENDNOTE

Clarifying article attachment

ENDNOTE

Software for creating bibliographies

ENDNOTE
Chapter trailer
ENDNOTE
Article trailer
ENDNOTEExplanatory postscript
ENDNOTEAfterword
ENDNOTEArticle afterthought
ENDNOTEWhat a superscript in a text might refer one to
ENDNOTEPostscript
ENDNOTEPlace for additional info
ENDNOTEBit of appended text
ENDNOTEOne may close a book