A faunistic database on the spiders of the Caucasus
Dmitri Logunov just pointed out to me, that all articles published in Arthropoda Selecta are available as PDF downloads via the British Arachnological Society (tab ‘Hosted Sites’).

"... a thorough collecting of Arachnids in Transcaucasia would yield a magnificent prey because, namely in spiders, an astonishing richness in both individuals and species made itself noticeable." L. Koch (1878)