What is "superficial gravity" I have seen the term superficial gravity used and it seems to be equivalent to surface gravity

seen, e.g., here http://arxiv.org/pdf/1701.02295

Is there any difference between superficial and surface gravity? When should one be using one or the other?
The term "superficial" means "on the surface," so "superficial gravity" is the same as surface gravity. As @pela pointed out in the comments, the author of the article is Portuguese and in that language the word for surface is 'superficie.'