In-depth studies of linkages
Oceanic
Geraghty, Paul A. 1983. The history of the Fijian languages (Oceanic Linguistics Special Publication No. 19). Honolulu: University of Hawaii Press.
The first systematic study of a linkage (avant la lettre).
Ross, Malcolm D. 1988. Proto Oceanic and the Austronesian languages of Western Melanesia (Pacific Linguistics, Series C – 98). Canberra: Pacific Linguistics.
The publication that introduced the term “linkage”.
Indo-European
Porzig, Walter. 1954. Die Gliederung des indogermanischen Sprachgebiets. Heidelberg: Carl Winter Universitätsverlag.
Indo-Aryan
Toulmin, Matthew. 2009. From linguistic to sociolinguistic reconstruction. Canberra: Pacific Linguistics.