* {{Cite book | ref = harv | last = Hult| first = Arne| title = On the Development of the Present Active Participle in Bulgarian| url = https://books.google.com/books?id=-kViAAAAMAAJ | year = 1991| publisher = Institutum Slavicum Universitatis Gothoburgensis| isbn = 978-91-86094-11-9| pages = 26}}▼
{{refbegin|30em}}
* {{Cite book | ref = harv | last = Woodard| first = Roger D.| title = The Ancient Languages of Asia and the Americas| url = https://books.google.com/books?id=UQpAuNIP4oIC | year = 2008| publisher = Cambridge University Press| isbn = 978-0-521-68494-1| pages = 1–2}}, Quote: "The earliest form of this 'oldest' language, Sanskrit, is the one found in the ancient Brahmanic text called the Rigveda, composed c. 1500 BC. The date makes Sanskrit one of the three earliest of the well-documented languages of the Indo-European family - the other two being Old Hittite and Myceanaean Greek - and, in keeping with its early appearance, Sanskrit has been a cornerstone in the reconstruction of the parent language of the Indo-European family - Proto-Indo-European."</ref><ref>{{citebook| last = Hult| first = Arne| title = On the Development of the Present Active Participle in Bulgarian| url = https://books.google.com/books?id=-kViAAAAMAAJ | year = 1991| publisher = Institutum Slavicum Universitatis Gothoburgensis| isbn = 978-91-86094-11-9| pages = 26}}
▲* {{Cite book | ref = harv | last = HultWoodard| first = ArneRoger D.| title = OnThe theAncient DevelopmentLanguages of theAsia Presentand Active Participle inthe BulgarianAmericas| url = https://books.google.com/books?id=-kViAAAAMAAJUQpAuNIP4oIC | year = 19912008| publisher = Institutum SlavicumCambridge UniversitatisUniversity GothoburgensisPress| isbn = 978-910-86094521-1168494-91| pages = 261–2}}
* {{Cite book | ref = harv | last = Reinöhl| first = Uta| title = Grammaticalization and the Rise of Configurationality in Indo-Aryan| url = https://books.google.com/books?id=nR_4CwAAQBAJ | year = 2016| publisher = Oxford University Press| isbn = 978-0-19-873666-0| pages = xiv, 1–16}}
* {{Cite book | ref = harv | last = Pollock| first = Sheldon| title = The Language of the Gods in the World of Men: Sanskrit, Culture, and Power in Premodern India| url = https://books.google.com/books?id=CMskDQAAQBAJ&pg=PA14| year = 2006| publisher = University of California Press| isbn = 978-0-520-24500-6| pages = 14}}
