Rabindranath Tagore FRAS (/rəˈbɪndrənɑːt tæˈɡɔːr/ (listen); pronounced; 7 May 1861 – 7 August 1941) was a Bengali polymath who worked as a poet, writer, playwright, composer, philosopher, social reformer and painter. He reshaped Bengali literature and music as well as Indian art with Contextual Modernism in the late 19th and early 20th centuries. Author of the "profoundly sensitive, fresh and beautiful" poetry of Gitanjali, he became in 1913 the first non-European and the first lyricist to win the Nobel Prize in Literature. Tagore's poetic songs were viewed as spiritual and mercurial; however, his "elegant prose and magical poetry" remain largely unknown outside Bengal. He was a fellow of the Royal Asiatic Society. Referred to as "the Bard of Bengal", Tagore was known by sobriquets: Gurudeb, Kobiguru, Biswokobi.
From the passage provided, extract the sobriquets Tagore was known by. Separate them with a comma.
Gurudeb, Kobiguru, Biswokobi.