Spyrochiro

Now that our Nihonto has been identified as Fujiwara sadayuki, We're trying to figure out where to go next. I would like to find some detailed information about it, like (age, period, school, etc). Can any of you recommend a reference book that has worked well for you in the past? Also, the sword has not been well maintained over the past 70 years. We have no desire to sell it, but it should be better kept. I would like to get a hands-on assessment of its condition and the details concerning its restoration. I live in the Houston area, does anyone here know someone in the area who can give me an accurate assessment and maybe even do the the restoration work? If not, do you know a good place/website to start looking for someone?

This sword was recovered in Okinawa after WWII. It has recently come to me from family. The Tsuba is completely missing and most components, with the exception of the blade are in poor shape. I am considering having it restored but I would like a much more detailed history before I do so. The first Picture is the first 2 characters, and I am pretty sure they are "Fujiwara". I think the final character on the second picture is "yuki". I am having a beast of a time finding the meaning of the symbol just above "yuki" on the second photo. If someone could give me a hand, I would really appreciate it. Thanks