I look up one article on another fairy tale (8)
I believe the answer is:
iolanthe
'fairy tale' is the definition.
(Iolanthe is a fairy tale character)
'i look up one article on' is the wordplay.
'look' becomes 'lo' ('lo' is an archaic exclamation meaning 'look!').
'up' says the letters should be written backwards (in down clue: letters go upwards).
'one' becomes 'the' (both can introduce a definite example of something).
'article' becomes 'an' (indefinite article).
'on' says to put letters next to each other.
'lo' written backwards gives 'ol'.
'the' after 'an' is 'anthe'.
'i'+'ol'+'anthe'='IOLANTHE'
'another' acts as a link.
This may not be right. It may be part of another bit of the clue.
(Other definitions for iolanthe that I've seen before include "G & S' alternative for "The Peer and the Peri"" , "G&S piece" , "G&S's eponymous fairy" , "Staged work" , "G&S operetta" .)