Akther, Rubina, et al. “Cardiac Autonomic Impairment and Low Serum Vitamin B12 and High Homocysteine Level in Parkinson’s Disease -Frequency Domain Analysis Ofheartratevariability”. Journal of Bangladesh Society of Physiologist, vol. 19, no. 2, Feb. 2025, pp. 46-54, doi:10.3329/jbsp.v19i2.79575.