1. Archive of Formal Proofs.
http://afp.sourceforge.net/
2. Immutable non-strict arrays in Haskell.
http://hackage.haskell.org/package/array-0.5.2.0/docs/Data-Array.html
3. Matlab documentation. Definition of Hermite Normal Form.
http://es.mathworks.com/help/symbolic/hermiteform.html#butzrp_-5
4. The Vector structure in SML.
http://sml-family.org/Basis/vector.html
5. HOL interactive theorem prover (2016).
https://hol-theorem-prover.org/