From QSPR Wiki
ARTICLEID is used to identify article (or other source of information) when uploading record in BATCH UPLOAD. The easiest way is to use PubMed ID (PMID) of the article from PubMed as the ARTICLEID. In this case the article will be automatically retrieved from PubMed.
For example, article
Huuskonen JJ, Livingstone DJ, Tetko IV. Neural network modeling for estimation of partition coefficient based on atom-type electrotopological state indices J Chem Inf Comput Sci. 2000 Jul;40(4):947-55 has PMID 10955523
If the article is not in PubMed, one can also download a reference to it or create its reference in the Articles Browser and use its QID. Indeed, most of journals have now export option. Just check it and export reference in RIS format (with abstract) and upload it using "External format upload" button in Article Editor.