2008 April 1, Ilan Caron, “Guardian Cryptic Crossword No. 24350 set by Brendan”, inrec.puzzles.crosswords[1] (Usenet):
The puzzle itself was fairly easy however there was an elegantnina based on the middle entry (INSIDE STORY) in which each of the across answers hid a synonym of "story", e.g. 5A and 6A were: STABle gendER.
2014 August 10, Brian Bethune, “The crossword’s meandering 100-year journey”, inMaclean's[2]:
Ninas may or may not be present and, even if one is there, it can go unnoticed because, not being intrinsic to the solution, its presence is not advertised—or because it is so well hidden.
2014, Alan Connor,The Crossword Century: 100 Years of Witty Wordplay, Ingenious Puzzles, and Linguistic Mischief, Penguin,→ISBN:
Other “personal”ninas are happier and subtler: birthday wishes to loved ones, which, ultimately, have only one intended reader
This is used where there is more than one addressee, as a simpler way of sayingni [1st referrent] …at ni [last referrent] (e.g.nina Pedro at Juan).
Where it precedes one name, this refers to the person and others surrounding them (e.g.nina Pedro refers to Pedro and anyone other around him, usually unspecified).