Our customer List Labs made an astute observation. They found that the “publication date” is in the future for some of the citations we compiled for them. For example:
Peripheral and central anatomical organization of cutaneous afferent subtypes in a rat nociceptive intersegmental spinal reflex
If it is published in the future, how were we able to find it now in May, 2017?
This is actually normal. Since many journals have this “early online access” mechanism, we can often find papers ahead of its “official” publication date. This is exactly what is happening here. See screenshot below (notice what is highlighted)
Publication date has a fuzzy definition now. It can be the “official (print) publication date”, or the first time it appears online, or the first time it is indexed by major search engine such as Google, Google Scholar, PubMed, etc. In the data we provide to customers, we use the “official (print) publication date”.