Reduction algorithm:
A Unified Algorithm for Determining the Reduced (Niggli) Cell
I. Krivy and B. Gruber
Acta Cryst. (1976) A32, 297-298.

and/or
Algorithm of Liang Zuo, et al.
Acta Cryst. (1995) A51, 943-945.

Convenient Lattice Transformation:
Lattice Symmetry Determination
A.D. Mighell and J.R. Rodgers
Acta Cryst. (1980) A36, 321-326.

and
Cell Reduction and Lattice Symmetry Determination:
William Clegg
Acta Cryst. (1981) A37, 913-915.

Application in electron diffraction experiments:
K.H. Kuo
Acta physica sinica (1978). 27, 160-167(in Chinese).