I think it depends on which species is being treated and what is the objective of analyzing the germination. Some recommend the ISTA manual (https://www.seedtest.org/en/Rules%202019/free-2019-rules-chapters-_content---1--3410.html) but it costs an amount in EUROS that is necesary to find out - There must be other academic material free of cost. It is best to see how authors have been handled in the specific bibliography (academic not in the industry). I believe that a manual that is expensive in EUROS is for people who work in a trade or industry, not for those of us who do science in the academic part that we usually have scarce resources (we must separate business from science). Science and business are not the same, they are governed by different interests. The seeds particularly, at this time are a problem because there are big monetary issues.