I had the same problem when trying to research the Australian and German Patent database. The Australian patents were applied for but abandoned The German references
might be the German indexing number for EP or WIPO in the German database Another problem occurs in the Titles because a translation from an English language patent to
Japanese or German and the when translated back by machine translation the titles are different
An example of this is the Japanese cross reference handed out at the Bremen conferences and posted here at ionizationx Sometimes the denotation and connotation
issues in translation result in an approximation of the meaning. Add to that , the need by Meyer to invent phrases to describe hitherto unknown processes adds to the imprecision
and "fuzziness" Frank Close, the head of the Theoretical Physics Dept. over at Rutherford Laboratories ran into the same problem....He discusses this in the "It Runs on Water" programme.
The following link is a to years and serial number for a US patent and has a xx/yyyy format
Since the 1981 year does not go up to 302807 for that year, use a google search for 6/303807 ( dropped the zero in the x field
which results in a link to US patent US4613304A titled "Gas Electrical Hydrogen Generator"
Link to table:
https://www.uspto.gov/web/offices/ac/ido/oeip/taf/filingyr.htmregards
Just google 4613304A and download the pdf from google.patents or the US patent office
