The New Paper : The edition of the Singaporean newspaper.
While your query specifies October, this is the primary academic paper matching those specific identifiers (Paper 18, Volume 21, 2018). Other notable publications matching parts of your description from October 2018 include: : 18 – Volume 21 – October 2018
World Economic Outlook, October 2018 : An IMF report titled "Challenges to Steady Growth". : The New Paper : The edition of the Singaporean newspaper
Could you clarify the (e.g., agriculture, economics, health) to help identify the exact document you need? 2018 - Volume 21, Journal of the International AIDS Society : Could you clarify the (e
Journal of the International AIDS Society : Volume 21, Issue 10 (October 2018) contains research on regional differences in HIV prevention.
Value in Health : Volume 21, Issue 10 (October 2018), covering health economics and outcomes research. :
The citation provided appears to refer to by Eloi, which was published as Paper 18 in Volume 21 of the journal Australasian Agribusiness Perspectives in December 2018 .