Some links for ZX Assemlby programming

Making games in ZX Spectrum assembly book ( russian lang.):
http://zxpress.ru/book.php?id=2

How to write ZX Spectrum games tutorial in English:
https://chuntey.wordpress.com/2012/12/18/how-to-write-zx-spectrum-games-chapter-1/

Spectrum ROM routines:
http://skoolkit.ca/disassemblies/rom/asm/2852.html

Z80 instruction set:
http://clrhome.org/table/

Group in FB dedicated for Z80 assembly programming:
https://www.facebook.com/groups/z80asm/

WOS forum link:
http://www.worldofspectrum.org/forums/categories/assembler

Another forum (ru):
http://zx-pk.ru/forums/14-programmirovanie.html

Some more books (ru):
http://vtrdos.ru/