deletion valid reference on gemstone page Hi You deleted a reference I ve been using on and off for years According to Wikipedia guidelines point 3 online textbooks the reference is in fact according wikipedia linking guidelines The page shows over 100 full text copyright free antique scientific publications on gemological topics and is furthermore a non commercial page without and advertisements The reference I am referring to is tThis library page Unless you have a valid reason to delete the reference I will be placing it back I would furthermore appreciate it if you would contact me before deleting references I add I am take great care in the sources I use Thank you