Please note that within this document, the term "Tzitzit" refers to the fringe-strings which are worn on the corners of four-cornered garments.
Legal Issues
Defining the term, "Tzitzit": Menachot 41b, 42a
Whether the mitzvah is Person-Based, or Garment-Based: Shabbat 131a-b; Menachot 41a, 42b
Whether having strings on all of the four corners constitutes four separate Mitzvot, or they are all necessary to fulfill a single mitzvah: Menachot 37b-38a
Not travelling four cubits without Tzitzit: Shabbat 118b