The best is Codex Borgia in its restored version. You can find it at Amazon for a very decent price. The others are difficult. You can at best find facsimiles but practically no one have access to the originals since there are only FOUR that survived the Spanish purifying spree. FOUR out of estimated hundreds. Michael Coe is the best specialist at the present moment and his books must be in all libraries. I also like John Montgomery and particularly his Dictionary of Maya hieroglyphs, though they are NOT hieroglyphs. Maya is not a first articulation language like old Egyptian (an old Semitic language). Maya is definitely a third articulation language and their writing system is essentially based on a syllabary. I still hesitate between agglutinative or synthetic, though I am leaning towards synthetic. I have to compare Maya and Aboriginal languages. For me that’s the only migratory route that make sense. But it is a question of time.