Luay et al. 2005, p. 1: "The Germanic subfamily especially seemed to exhibit non-treelike behavior, evidently acquiring some of its characteristics from its neighbors rather than (only) from its direct ancestors. [...] [T]he internal diversification of West Germanic is known to have been radically non-treelike [...]." Luay, Nakhleh; Ringe, Don; Warnow, Tandy (2005). «Perfect Phylogenetic Networks: A New Methodology for Reconstructing the Evolutionary History of Natural Languages». Language. 81 (2). doi:10.1353/lan.2005.0078;
Lehmann, W. P. (1961). «A Definition of Proto-Germanic: A Study in the Chronological Delimitation of Languages». Language. 37 (1): 67–74. JSTOR411250. doi:10.2307/411250
Antonsen, Elmer H. (1965). «On Defining Stages in Prehistoric German». Language. 41 (1): 19–36. JSTOR411849. doi:10.2307/411849
Lass 1994, p. 18. Lass, Roger (1994). «2 - Indo-European to Proto-Germanic to West Germanic». In: Lass, Roger. Old English. A Historical Linguistic Companion. Reino Unido: Cambridge University Press. ISBN9780521458481. doi:10.1017/CBO9780511621000.005;
Lehmann, W. P. (1961). «A Definition of Proto-Germanic: A Study in the Chronological Delimitation of Languages». Language. 37 (1): 67–74. JSTOR411250. doi:10.2307/411250
Lehmann 2007, 1.10. The Development of Germanic. Lehmann, Winfred P. (2007). Slocum, Jonathan, ed. A Grammar of Proto-Germanic. Austin: UTEXAS Linguistics Research Center;
Lehmann 2007, 5.1. Structure of the Sentence as SOV. Lehmann, Winfred P. (2007). Slocum, Jonathan, ed. A Grammar of Proto-Germanic. Austin: UTEXAS Linguistics Research Center;
Lehmann 2007, Caps. 5.1.1. Evidence for OV Order in Simple Clauses e 5.1.2. Order in Comparative Constructions. Lehmann, Winfred P. (2007). Slocum, Jonathan, ed. A Grammar of Proto-Germanic. Austin: UTEXAS Linguistics Research Center;
Lehmann 2007, Cap. 5.4. Expression of Negation. Lehmann, Winfred P. (2007). Slocum, Jonathan, ed. A Grammar of Proto-Germanic. Austin: UTEXAS Linguistics Research Center;
Lehmann 2007, Cap. 5.6. Expression of Tense and Aspect. Lehmann, Winfred P. (2007). Slocum, Jonathan, ed. A Grammar of Proto-Germanic. Austin: UTEXAS Linguistics Research Center;
Lehmann 2007, VI. Semantics and Culture. Lehmann, Winfred P. (2007). Slocum, Jonathan, ed. A Grammar of Proto-Germanic. Austin: UTEXAS Linguistics Research Center;
Lehmann 2007, Cap. 6.1.2. Economic and Personal Practices. Lehmann, Winfred P. (2007). Slocum, Jonathan, ed. A Grammar of Proto-Germanic. Austin: UTEXAS Linguistics Research Center;