Glad that Feng found the proof, I was actually surprised about what Feng was exactly looking for. It turned out to be that he wanted a proof for this inequality.
Definitely, the proof comes from Riemann Zeta function which asymptotically approaches one at x goes to infinity. The Riemann Zeta function at even arguments is expressed in terms of the Bernoulli numbers.
What I wanted is a site, where the inequality existed, or a proof of the inequality. I did not find a site, but a proof.
Now we may pose a new question: can one discover an explicit lower bound for the ratio $|B2n+2|/|B2n|$ of two consecutive Bernoulli numbers with even indexes?
In the beginning, I did mean that I needed a site to cite. Because I did not find the site, I desired to find a proof, and I luckily made a real success.
Now we should pay our attention on discovering an explicit lower bound for the ratio $|B2n+2|/|B2n|$ of two consecutive Bernoulli numbers with even indexes.
In my opinion, it is very narrow and parochial to deride a foreigner not speaking in English. I think it is very ridiculous to deride a foreigner not speaking in English. Don't you think so? I think so.
I am glad to announce a news: I have obtained a double inequality for bounding the ratio $|B2n+2|/|B2n|$ of two consecutive Bernoulli numbers with even indexes.
Why do I need " these shallow games with 19th century numbers"? Here I do not know how to simply tell you in English the rationale. If you contact me, I may send you a completed manuscript by e-mail.
Anyway, I appreciate everyone who ever wrote and helped me here, because I learned very much from you, including mathematics, english, and personality. Thank all!
Thank you for your free criticism and advice, but I can not understand you nearly. Despite this, if you have more time, please continue to write your free criticism and advice more and more. You are welcome.
To the best of my knowledge, I do not know whether there are other known estimates for ratios of Bernoulli numbers. If you find any, please let me know. Thank a lot.
Thank Peter T Breuer for so much new information to me.
Moreover, I need a reference containing the integral analogue of Cauchy-Binet identity (a formula looks like the one in the attached picture), but I can not find such a reference published in English. Could you please help me? Anyway, thank you in advance.
[1] Feng Qi, A double inequality for ratios of Bernoulli numbers, ResearchGate Dataset, available online at http://dx.doi.org/10.13140/2.1.2367.2962.
[2] Feng Qi, A double inequality for ratios of Bernoulli numbers, RGMIA Research Report Collection 17 (2014), Article 103, 4 pages; Available online at http://rgmia.org/v17.php.
Feng Qi, A double inequality for ratios of the Bernoulli numbers, ResearchGate Dataset (2015), available online at http://dx.doi.org/10.13140/RG.2.1.3461.2641.
The following formally published papers are related to this question:
[1] Feng Qi, A double inequality for the ratio of two non-zero neighbouring Bernoulli numbers, Journal of Computational and Applied Mathematics 351 (2019), 1--5; available online at https://doi.org/10.1016/j.cam.2018.10.049
[2] Feng Qi, Notes on a double inequality for ratios of any two neighbouring non-zero Bernoulli numbers, Turkish Journal of Analysis and Number Theory 6 (2018), no. 5, 129--131; available online at https://doi.org/10.12691/tjant-6-5-1