Rephrase "to the best of my knowledge"

In my master thesis I want to state that I did not find any related work except for one paper. In scientific papers the authors often use the phrase "To the best of our knowledge, ...". However since I have no co-authors I can not use "our" and I also don't want to speak in first person so I also don't want to use "to the best of my knowledge" as that would sound strange somehow. Is there a formulation which expresses the same information but without speaking in first person ?

"To the best of my knowledge" sounds too legal for a Master's Thesis, "I looked and did not find any related work except for one paper" is too informal.

The following expresses the same information formally, without speaking in first person

A thorough search of the relevant literature yielded only one related article.

The fact that you, the author, did the search or vouch for the thoroughness is implied. Your search may have missed a relevant paper, but all anyone can expect is that you be conscientious and thorough.

Pursuing Hot Licks' comment:

"as far as this author knows" About 2,590 results

is quite well represented out there at Google Books in relatively recent times.

The funny thing is that:

"to the best of my knowledge" 13,900,000 results

shows up mainly in 19C references, while

"to the best of this author's knowledge" About 3,740 results

has many present day ones.

I wonder of the members of the learned societies have become more remote/formal lately :-)