Sometimes Wikipedia fails us when we are determining public domain works.
I recently found this useful blog, that has biographical information about a number of lesser-known writers. I found the birth & death dates of translator Margaret Armour on this blog, and I thank google for sending me there.
http://desturmobed.blogspot.jp/
I hope you might find it useful, along with
http://www.booksandwriters.co.uk/
Here is a link that pdurrant shared some time ago that is *really* extensive ---
http://www.authorandbookinfo.com/ngcoba/
Here is a good resource for *magazine articles*:
http://www.philsp.com/homeville/fmi/a/a4.htm
The PhilSP site is ENORMOUS and has lots of cross-referenced magazine databases. --- Once you have the magazine issue information, you can use
http://onlinebooks.library.upenn.edu/ to seek the magazines, or go directly to HathiTrust
https://www.hathitrust.org/ and hunt them down there.
Also, just as a note of interest, HathiTrust often displays the author birth & death dates on the "catalog entry" for the book title. archive.org does also.
Do you have similar resources to share?