Bip39 seed phrase generator http://www.mediafire.com/file/uilrjfajg2ami24/pdf-14673-57158.pdf It is important that the mnemonic sentences are generated from randomly selected numbers! These numbers could be produced in a number of other ways, that happen to be described in other content articles in this article, like "What is an RNG" and Seed Phrase Generation. https://kingbookmark.com/story20064643/bip39-import-bip39-generator-secrets-https-dzen-ru-bip39-phrase-com