Legal status (The legal status 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 status listed.)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ERNEST GEOFFREY HELLIWELL
Original Assignee
ERNEST GEOFFREY HELLIWELL
Publication date
Application grantedgrantedCritical
Publication of CA443579ApublicationCriticalpatent/CA443579A/fr