dear #biology friends... I want to learn more about this:

"#Histone H4 is encoded in multiple genes at different loci including: HIST1H4A, HIST1H4B, HIST1H4C, HIST1H4D, HIST1H4E, HIST1H4F, HIST1H4G, HIST1H4H, HIST1H4I, HIST1H4J, HIST1H4K, HIST1H4L, HIST2H4A, HIST2H4B, HIST4H4."

Who can recommend a good read? I have questions like: are all genes expressed at the same time? Equally? How are all regulated? Do they all code the exact same 102 AAs? what about the biology of the up to 33 other AAs?