R. VIELMA-RONDÓN, J. OVALLES-DURÁN, A. LEÓN-LEAL, and A. MEDINA, “Nutritional value of earthworm flour (Eisenia foetida) as a source of amino acids and its quantitative estimation through reversed phase Chromatography (HPLC) and pre-column derivation with o-phthalaldehyde (OPA)”, Ars Pharm, vol. 44, no. 1, pp. 43–58, Dec. 2002.