References:

1) Antimo D'Aniello. D-Aspartic acid: An endogenous amino acid with an important neuroendocrine role. Brain Research Reviews. Vol. 53: 215-234.

2) Aspartic Acid – Important Intermediate in the Citric Acid Cycle. Retrieved Jan 4, 2008.

3) Amino Acids & Proteins, The Canadian  Holistic Health College. Retrieved Jan  4, 2008.