As somehow expected, the first I run into is an undefined expression:
http://www.ioannisxydous.gr/SEPPv7.pdf p.4/eq(3):
is nonsense.
There is e.g. either
∫_∂V dA
denoting a surface integral at ∂V
or
∫ dV
denoting either a (divergent, because there are no limits given) volume integral OR or the full domain integral of the exterior derivative of a differential form "V" (in which case it would be misleadingly labeled)
So what would my reward for reading this paper and guessing what that kind of fantasy formalism is meant to mean?