Direct links to free Springer books (pdf versions) Graduate texts in mathematics duplicates = multiple editions A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen
Safest way to clean up boot partition - Ubuntu 14.04LTS-x64, Ubuntu 16.04LTS-x64 Reference Case I: if /boot is not 100% full and apt is working 1. Check the current kernel version $ uname -r