The pseudonym dictionary is more than just a list of author's and their pseudonyms as it includes in many cases the publications and dates when a particular pseudonym was used.
The periodical bibliographies included here are:
Русская периодическая печать, 1702—1894. — 1959 Русская периодическая печать, 1895 — октябрь 1917. — 1957 Лисовский. Библиография русской периодической печати, 1703—1900 гг.: Материалы для истории русской журналистики: В 2 кн. Библиография периодических изданий России, 1901—1916 Сводный каталог сериальных изданий России, 1801—1825.
If you are seeking information on periodical publications from the pre-revolutionary period this will be the best site to consult. The nature of the information in each of these sources, and its organization varies quite alot. So while Lisovskii's bibliography is probably the most comprehensive list of titles, Русская периодическая печать includes the most detailed descriptions of the type of material included in each publication. Библиография периодических изданий России Rossii is the most comprehensive list of titles for the late imperial period and has the added advantage of an index volume with a subject list. Also, each of its entries include the issues that were published for each year and their volume/issue numbers.
The final title in this list has yet to be scanned for the project.