Fracchia 2005, p. 34. Fracchia, Joseph (2005). "Beyond the Human-Nature Debate: Human Corporeal Organisation as the 'First Fact' of Historical Materialism". Historical Materialism. 13 (1): 33–62. doi:10.1163/1569206053620915. – via EBSCO's Academic Search Complete (subscription required)
ebsco.com
McLellan 1984, p. 159. McLellan, David (1984). "Marx and Human Nature (Book)". Political Studies. 32 (1). – via EBSCO's Academic Search Complete (subscription required)
Fracchia 2005, p. 34. Fracchia, Joseph (2005). "Beyond the Human-Nature Debate: Human Corporeal Organisation as the 'First Fact' of Historical Materialism". Historical Materialism. 13 (1): 33–62. doi:10.1163/1569206053620915. – via EBSCO's Academic Search Complete (subscription required)