Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Houston Eng ResfiledCriticalHouston Eng Res
Priority to FI3172/74ApriorityCriticalpatent/FI317274A7/fi
Publication of FI317274A7publicationCriticalpatent/FI317274A7/fi