Dear Martin,

Thank you for your very clear and concise answer. It helps me out.

Dear sir, madam, I have a number of patents downloaded from PATSTAT (edition 2018B), for which I retrieved the IPC classes (4 digits level). As these codes are not telling much, I would like to link each code to its description. Using the table TLS901_TECHN_FIELD_IPC, I can for instance link the IPC...