This challenging Mexico "Conserva" series, globally known and very popular, is being collected according to the criteria of the 4 papers, going well beyond Scott and Michel listings, if you have not done so yet, go ahead and start studying the characteristics of the 4 papers, 

The paper classification is made according to:  watermark, luminescence on anverse and reverse sides and satin finish. The stamp classification add: design, denomination, imprint ( TIEV or ROMO ), perforation, color, and security burelage.

The number of stamps listed or classified for complete Mexico "Conserva"  serie are: Scott 131,  Michel 130,  etiangui 162.

All Mexico Conserva etiangui 162 stamps could be found here at etiangui Ebay store  ( stores.ebay.com/etiangui/ )