The article regards source study commentary of A.T. Bolotov’s autobiographi­cal work. He was the famous Russian educator of the second half of the 18th century who put his recollections into the form of letters not intended for publication, which was common in the European tradition of that time. So the book sources used are often implicit, such as a retelling, a mention of the author, or even a combination of several sources. Being fluent in German Bolotov belonged to a generation that emerged during a time when Francophony had not yet become established among the educated nobility. The identification of some of the German sources is challenging due to the author’s free-flowing style in his extensive historical and literary work. Several examples discussed in the article highlight the challenges faced by modern commentators of this type of text.