Here's the user manual for an old, chronometer-type Russian slide rule.
My GnuPG key
We can communicate via secure e-mail using GnuPG / OpenPGP, which I strongly recommend. More details in this guide.
For those seeking to write to me, here is my public GnuPG key:
pub 4096R/0xC2B8B57AAAFC29CE 2016-02-29
Fingerprint=EA7F F4E9 08A4 B62D 34E0 9889 C2B8 B57A AAFC 29CE
sub 4096/0x059CDF01110D7CE9 2016-02-29