He wrote the following textbooks: "A Bulgarian Primer" (1866), "A Big Bulgarian Reader" (1868), "Mother tongue" (1874), "Short Land description (Geography)" (1868), "Short Religion Book" (1868), which were published in Istanbul.[4] Shapkarev criticized the dominance of eastern Bulgarian and even declared that it was incomprehensible in Macedonia. In his Great Bulgarian Textbook (Golema balgarska chitanka) from 1868, which he authored under the pseudonym "One Macedonian" (Edin Makedonets), he stated his intention to write in a language understandable to his compatriots, the Macedonian Bulgarians. He also announced a project of a dictionary that would contain translation from Macedonian into Upper Bulgarian and vice versa. This activity was condemned by the Bulgarian press, which even accused him of advocating the existence of a separate Macedonian language and a distinct history of the Macedonian people.[7][8] Bulgarian philologist Marin Drinov rejected his proposal for a mixed eastern and western Bulgarian (Macedonian) basis of the Bulgarian standard language.[7]
Shapkarev was a contributor of many Bulgarian newspapers and magazines – "Tsarigradski vestnik" (Constantinople newspaper), "Gayda" (Bagpipe), "Macedonia", "Pravo" (Justice), "Savetnik" (Adviser), "Balgarska pchela" (Bulgarian bee) and others. Shapkarev was a collaborator of the revolutionary Georgi Rakovski and in the field of ethnography, he assisted the Miladinov brothers.
^Autobiography of Kuzman Shapkarev, 1864, Macedonian review, year ІІІ, 1927, № 1, № 2.; Also in "Materials for the Revival of Bulgarian national spirit in Macedonia".
^MacDermott, Mercia (1998). Bulgarian Folk Customs. Jessica Kingsley. p. 31. ISBN1-85302-485-6.
^Maria Couroucli; Tchavdar Marinov, eds. (2017). Balkan Heritages: Negotiating History and Culture. Taylor & Francis. p. 20. ISBN9781134800759.
^ abcDenis Š Ljuljanović (2023). Imagining Macedonia in the Age of Empire: State Policies, Networks and Violence (1878-1912). Lit Verlag. pp. 169–170. ISBN9783643914460.
^ abcDimitar Bechev (2019). Historical Dictionary of North Macedonia. Rowman & Littlefield. p. 263. ISBN9781538119624.
^Dimitris Keridis; John Brady Kiesling, eds. (2020). Thessaloniki: A City in Transition, 1912-2012. Routledge, Taylor & Francis Group. pp. 67–68. ISBN9780429201561.
^ abcTchavdar Marinov; Roumen Daskalov (2013). "In Defense of the Native Tongue: The Standardization of the Macedonian Language and the Bulgarian-Macedonian Linguistic Controversies". Entangled Histories of the Balkans - Volume One. Brill. pp. 285, 441–443. ISBN9789004250765.