[Lowe 2014] Lowe, Bryan D. “The Scripture on Saving and Protecting Body and Life: An Introduction and Translation.” Journal of Chinese Buddhist Studies 27 (2014): 1-34.
— 10, 12
"Soon after the appearance of these powerful deities [viz. the "six spirits" 六神] in Daoist scripture, Buddhist authors quickly adopted them in a text--the aforementioned [Yi suan jing 益算經]--that almost perfectly mirrors a Daoist one with the exception of a few key alterations, a common practice that may have emerged as priests and monks competed with one another for patronage." Lowe gives further details, and refers to Mollier (2008): 106-113 and 131-133; and Robson (2008): 163-166.