Hello, sorry for writing in English! I am researching one of the above-mentioned personalities, Boris Venkov Mihov, he was first cousin of my great-grandfather Krum Mihov from Letnitsa, Bulgaria. My grandmother told me a lot about him, when he left Bulgaria he was a highly educated and progressive young man, from a long lineage of revolutionaries, and his family thought that he "went to Russia to study". What really happened to him I didn't know until I googled his name and saw your article. Do you have any more information on him? Any of his writings, for which he was arrested and (I suppose) silenced? Best wishes, Tzenka