There are only a few scholars that I know of that have published studies on Tagore settings and Tagore's influence on Western style composers. The below table aims at providing an overview of these publications, including those focusing on one composer's settings in particular. Also included are some publications on Rabindra Sangeet.

The second table contains publications on Tagore on a more general level. An interesting overview of all publicly held Tagore related publications, as an author or as a topic, is available on Worldcat:

Some of the authors were closely befriended with Tagore. Here some notes on a few.

Arnold A. Bake (Netherlands, 1899-1963) studied at Visvabharati University with Pandit Bhim Rao Shastri in the 1920s. While there, Bake undertook the task to transcript Tagore's songs into western music notation, published by and available from the Musée Guimet in Paris. Bake gave many lectures in Europe, performing Tagore's songs, and travelled a lot across colonial India to study its local musical culture. His many recordings are preserved at the SOAS, University of London.

@2020Ezust, Emily (ed.)Inventory of art songs set to Tagore's texts
in: The Lied and Art Song Texts Page
2008Sen, SuddhaseelThe Art Song and Tagore: Settings by Western Composers
in: University of Toronto Quarterly, Volume 77-4, Fall 2008, pp 1110-1132
Publisher: University of Toronto
2002Vlad, RomanKarol Szymanowski's Four Songs, Op. 41 to Texts by Tagore
in: Piesn w twórczosci Karola Szymanowskiego i jemu wspólczesnych [The Songs of K. Szymanowski and His Contempories] pp 157-174
ISBN 0-916545-06-7

Publisher: Los Angeles: Polish Music Center, USC
2001de Groot, Rokuslecture
at: Tagore Festival
Publisher: Tropeninstituut Amsterdam (Netherlands)
1999de Groot, RokusVan Eden en Tagore: Ethiek en muziek
in: Tijdschrift van de Koninklijke Vereniging voor Nederlandse Muziekgeschiedenis, Vol. 49/2 (1999) pp 98-147
Publisher: Royal Society for Music History of The Netherlands
1997Mukherjee, Sisir KumarIndian Music Sources: the Songs of Tagore
in: Fontes Artis Musicae, pp 281-289 volume 44/3 July-September 1997
Publisher: AIBM - Association International des Bibliothèques Musicales
1996Gabrielová, JarmilaJosef Bohuslav Foerster: Liebeslieder des Rabindranath Tagore op. 96
in: Prag als Kunststadt 1911-1927: Die Prager Jahre von Alexander Zemlinsky (Archived link)
Publisher: Prague, Goethe-Institut (unpubl./archived)
1990Andraschke, Prof. Dr. PeterTagore-Vertonungen
in: Musik und Dichtung, pp 469-485
Quellen und Studien zur Musikgeschichte von der Antike bis in die Gegenwart, Band. 23
ISBN 3631418582

Publisher: Peter Lang, Frankfurt am Main
1989Head, RaymondThe flute and the harp: Rabindranath Tagore and western composers
in: Rabindranath Tagore - Perspectives in Time, pp 122-140 (Lago & Warwick ed.)
Publisher: London: The Macmillan Press Limited
1986Sheth, Nirupama & Ajit ShethTagore: Indian Film & Film Music
in print 1994
ISBN 95-902963

Publisher: Pankaj Mullick Research Foundation, Bombay
1984Coppola, Prof. Dr CarloRabindranath Tagore and Western composers: a preliminary essay
in: The Journal of South Asian Literature, vol. 19:2 pp 41-62
Publisher: Asian Studies Center, Michigan State University
1977Stuckenschmidt, H. H.Schönberg: His Life, World and Work (transl. from German)
Publisher: London
1962Rozhdestvenskaya, N.Romansy Sovyetskikh Kompozitorov Na Stikhi Rabindranata Tagora
Publisher: Gosudarstvennoe Muzykal'noe Izdatel'stvo, Moskva, 57pp
1961Bake, Dr. Arnold AdriaanTagore and Western Music
in: Rabindranath Tagore - A Centenary Volume - 1861-1961, pp 88-95 (Radhakrishnan ed.)
Publisher: Delhi: Sahitya Academy
1961Mukerji, Dhurjati PrasadTagore's Music
in: Rabindranath Tagore - A Centenary Volume - 1861-1961, pp 180-186 (Radhakrishnan ed.)
Publisher: Delhi: Sahitya Academy
1961Loewenbach, JosephLeos Janacek and Rabindranath Tagore
in: Rabindranath Tagore - A Centenary Volume - 1861-1961, pp 159-162 (Radhakrishnan ed.)
Publisher: Delhi: Sahitya Academy
1935Bake, Dr. Arnold AdriaanChansons de Rabindranath Tagore
Publisher: Paris
1921Janácek, LeošRabindranath Tagore
in: Lidové Noviny, Wednesday 22-6-1921
Publisher: Lidové Noviny

Starting point for the next table was a list created by Sujit K. Bhattacharjee (see), participating in Cyberperformance II: Self versus State on 19 December 1998, part of his course in 20th century literature with Professor Julia Evergreen Keefer, New York University. It consists of publications on Tagore in general.

2001Dyson, Ketaki KushariOn the Trail of Rabindranath Tagore and Victoria Ocampo
Parabaas - July 2001
Publisher: Parabaas
1997Dutta, Krishna, and Andrew RobinsonRabindranath Tagore: An Anthology
Publisher: New York: St. Martin's Press
1997Dutta, Krishna, and Andrew RobinsonSelected Letters of Rabindranath Tagore - Univ. of Cambridge Oriental Publications, No 53
Publisher: Cambridge, U.K.: Cambridge UP
1996Chatterjee, BhabatoshRabindranath Tagore and Modern Sensibility
Publisher: Oxford UP
1995Dutta, Krishna, and Andrew RobinsonRabindranath Tagore- The Myriad-Minded Man
Publisher: London: Bloomsbury Publishing Limited
1991Chatterjee, Monish RanjanRabindranath Tagore - Sadhaka of Universal Man, Baul of Infinite Songs
Publisher: University Dayton
1991Colussi, Luciano, ed.Universality in Tagore - Souvenir of a Symposium on Rabindranath Tagore
Publisher: Calcutta: Firma KLM
1990Dey, Suresh ChandraThe quest for music divine
Publisher: APH Publishing; The quest for music divine Door Suresh Chandra Dey Gepubliceerd door APH Publishing, 1990, ISBN 8170243017
1989Lago, Mary M., and Ronald Warwick (eds)Rabindranath Tagore - Perspectives in Time
Publisher: London: The Macmillan Press Limited
1985Iyengar, K.R. Srinivasa.Rabindranath Tagore - A Critical Introduction
Publisher: Delhi, Bangalore, and Jalandar: Sterling Publishers Private Limited
1980Kripalani, KrishnaRabindranath Tagore - A Biography
Publisher: Visva-Bharati, Calcutta
1977Chakravarty, Amiya, ed.Rabindranath Tagore - In Conversation with Albert Einstein
in: A Tagore Reader (transl. Mary Lago ed.)
Publisher: Connecticut: Greenwood Press
1976Lago, Mary MaloneRabindranath Tagore
Publisher: Boston: Twayne Publishers
1972Mukhopadhyaya, DhurjatiprosadaTagore - A Study
Publisher: Calcutta: Manisha Granthalaya
1965Chaudhury, Prabas JibanTagore on Literature and Aesthetics
Publisher: Calcutta: Rabindra Bharati
1961Radhakrishnan, Sarvepalli ed.Rabindranath Tagore - A Centenary Volume - 1861-1961
Publisher: Sahitya Akademi, New Delhi
1961Ghose, SisirkumarThe Later Poems of Tagore
Publisher: London: Asia Publishing House
1947Sen, SachinThe Political Thought of Tagore
Publisher: Calcutta: General Printers and Publishers Limited
1915Rhys, ErnestRabindranath Tagore - A Biographical Study
Publisher: London: Macmillan and Co., Limited
-Robinson, Andrewsee: Dutta, Krishna and Andrew Robinson