Contraction groups and passage to subgroups and quotients for endomorphisms of totally disconnected locally compact groups
T.P. Bywaters, H. Glöckner, S. Tornier, Israel Journal of Mathematics 227 (2018) 691–752.

Banach-Lie quotients, enlargibility, and universal complexifications
H. Glöckner, K.-H. Neeb, Journal Für Die Reine Und Angewandte Mathematik 560 (2003) 1–28.