I can't help but think there are some "Power Rangers References" in the 30 Sentai Encyclopedia done in a subtle way as there are "Super Sentai" references in Power Rangers. They are:
When Battle Fever J was featured, flags of different countries were featured. Inou Masumi carries the Kenyan flag, apparently that's where Zack Taylor the first black ranger of MMPR came from. Battle Kenya was also a black ranger. Go figure. On the other hand Sakura Nishihori's holding of America may give tribute to Kimberly Hart.
The Boukenger members mimic the Zyuranger pose also giving tribute to MMPR with Natsuki Mamiya probably paying tribute to Trini Kwan (whose character died as the actress Thuy Trang died by the Bio Killer Gun ahem car accident).
I think out of subtle reference, I think Eiji Takaoka looks like Andros in Power Rangers in Space.
Not really but again with Natsuki Mamiya, I think about how Time Force has two girls instead of one- a reference to Gomon wishing for two girls.
The other would be in the Gaoranger segment. We see Natsuki Mamiya dressed up as Gao Yellow, a reference to Taylor Eardhart being female while in Gaoranger, Gaku Washio was a male in the original. :-P