@online{huangndtopology,
  author       = {Huang, Xuanqiang Angelo},
  title        = {Topology Crash Course},
  organization = {Xuanqiang Angelo Huang's Blog},
  url          = {https://flecart.github.io/notes/topology-crash-course/},
  langid       = {english},
  abstract     = {A Crash Course in Topology \# This is a tour of the landmarks beyond Topological Spaces and Metric Spaces . Order of climb: first see how topologies are generated , then ascend the axiom ladder (separation, countability, compactness), then meet the invariants (algebraic topology,}
}