Hi Luis,
Sorry I also don't know why you can't find them.
About the K64 reference manual K64P144M120SF5RM.pdf, you can find on NXP website:
Arm® Cortex®-M4|Kinetis K64 120 MHz 32-bit MCUs|NXP

about the other two, it is about the ARM core document, you can find them on ARM website.
Hope it helps
Have a great day,
TIC
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