I am looking for some material (e.g. references, books, notes) to get started with Lie Groups and Lie Algebra.

My motivation is that I (eventually) want to understand the theory underpinning papers such as these.

The problem is, I am at the Rumsfeldian stage where *I don't know what I don'
t know.* The wikipedia page makes it clear that I lack several prerequisites in modern geometry.

So, what would be a proposed study path to get to this stage? My background is electronic engineering and am comfortable with associated topics (signal processing, estimation theory, Kalman Filtering, etc.)