There's "SPG Lubricants BP Cartridge Reloading Primer" by Mike Venturino and Steve Garbe, which covers 32-40 through to 50-140, and "Shooting Buffalo Rifles of the Old West" by Venturino which covers 40-70 Bottleneck through to 50-90.
Paul Matthews wrote "Loading the Black Powder Rifle Cartridge", and several others.
There's also "Loading Cartridges For The Original 45-70 Springfield Rifle And Carbine" by J.S and Pat Wolf, which goes into tremendous detail of load development using both smokeless and black.
They are all good reading.
Regards, DaveF.