General Relativity publication date

[Larry Smith <Larry.Smith@SNOW.EDU>]

I've seen references to General Relativity being published in 1915
<http://library.thinkquest.org/17508/Generalrelativity.html > and in 1916
<http://www.ncsa.uiuc.edu/Cyberia/NumRel/GenRelativity.html>.  Was it
accepted by the journal in 1915 and appeared in the printed issue in 1916
or what?  Is one a better year to quote than the other?

thanks,
Larry