Stacks Project
Unknown
Open, collaboratively written reference on algebraic geometry whose commutative algebra chapter is cited by tag number. This tag is a lemma on Jacobson rings, showing that localizing at one element preserves the Jacobson property. Readers need solid ring theory to follow it.
More resources on Fields
Wolfram MathWorld
MathWorld is an online mathematics encyclopedia from Wolfram Research offering detailed, browsable articles on topics across the math spectrum, including algebra, geometry, calculus, and number theory. Each entry includes definitions, theorems, formulas, diagrams, worked examples, and links to further reading.
nLab: Field
Research-level wiki entry defining fields as commutative rings with invertible nonzero elements, then examining constructive variants, the category of fields and links to related structures. Readers gain the categorical and constructive viewpoint that standard algebra textbooks usually omit.
Harvard MATH E-222: Abstract Algebra
Recorded Harvard Extension School lectures by Benedict Gross, following Michael Artin's textbook Algebra. Covers groups and group actions, vector spaces and linear operators, rings, and fields, with proofs throughout. Viewers gain a rigorous first grounding in algebraic structures and symmetry.