Good and thorough online and/or free Matroid Theory references? I'm studying a course on Matroid theory. Sadly, I can't really afford buying the textbook, so I only use the lecture notes, which aren't enough for me.   Are there any good and thorough online and or/free references on Matroid theory?   Thanks in advance for any assistance!
Books about matroids Could you recommend any approachable books/papers/texts about matroids (maybe a chapter from somewhere)? The ideal reference would contain multiple examples, present some intuitions and keep formalism to a necessary minimum.  I would appreciate any hints or appropriate sources.
How to learn commutative algebra? I want to learn commutative algebra from scratch. I was wondering, as you are experts in mathematics, what you think is the best way to learn commutative algebra? Is there any video course available for commutative algebra? Will there be some online course for commutative algebra on some website like Coursera, etc?  I know noncommutative algebra up to the Artin-Wedderburn Theorem. Also, I know group theory up to the Sylow theorems and Galois Theory. I also know some basic topology.  I'm new to this site so I don't know what tags I should add for this question. Please feel free to edit my question.  Edit 1: I want to learn commutative algebra for learning Algebraic Geometry.