This is all about oil and ZDDP (Zinc Dialkyl Dithio Phosphate). Very interesting and good reading material.
Please visit http://zddplus.com for lot of info about their Zinc and Phosphor ZDDP product and ordering.
Here is a few docs I keep as a backup in case the info would become unavailable at time.
TechBrief1 - Introducing ZDDPlus.pdf
TechBrief2 - ZDDP and Cam Wear - Just Another Engine Oil Myth.pdf
TechBrief3 - Lubrication Terminology.pdf
TechBrief4 - Oil & Additive Testing.pdf
TechBrief5 - Racing Oil as a Replacement for SM Oil.pdf
TechBrief6 - Diesel Oil Use in Classic and High-Performance Gasoline Engines.pdf
TechBrief7 - Oil Additive Dosing and Dilution rev4.pdf
TechBrief8 - The Automotive and Oil Industry vs. the Aftermarket Viewpoint on ZDDP.pdf
TechBrief9 - ZDDP and Oil Filters.pdf
TechBrief10 - Oil Base Stocks.pdf
TechBrief11 - Internal Combustion Engine Lubrication.pdf
TechBrief12 - ZDDP and Engine Break-in.pdf
TechBrief13 - Oil Viscosity.pdf
TechBrief14 - ZDDP and Pre-WWII Engines.pdf
TechBrief15 - Extended Oil Change Intervals.pdf
And this is in Dutch:
Info over ZDDP in Olie voor klassiekers.pdf