TheSpanish magazine of scientific documentation, in application of the established guidelinesby international committees of editorial ethics, and the non-rms of good practice inscientific publication, only admits original and unpublished articles, that is, not publishedpreviously in whole or in part in one or several journals, both in print andelectronics. Nor does he accept jobs thate have been sent or are in the process of beingevaluation for publication in another journal.Therefore, the direction of theSpanish magazine of scientific documentationhas decidedproceed to formal retractionof the following work:  Moreno-Cabo, M. and Solás-Portolés, JJ Bibliometric study of publicationsrelated to the pendulum between the years 1629 and 1885.Spanish Documentation Magazinescientific, 2008, vol. 31, n 4, p. 639-645. doi: 10.3989/redc.2008.4.647Since this is an exact duplication (except for three paragraphs of the introduction) of anotherpreviously posted:Solas-Portoles, JJ; Moreno Cabo, M.; Sanjosé López, V. Learning how to build thescience: the case of the pendulum.Latin American Journal of Physics Education, 2008, vol. 2, no. 1,p.47-50.  The work was submitted almost simultaneously to both journals. In the REDC it was received on the 20th ofNovember 2007, and was published in the last issue of 2008 (October-December), and inLAJPE, received on December 12, 2007,and was published on January 9, 2008.  None of the papers makes reference to the other, nor does it indicate the reasons they estimatedauthors to send a duplicate to two different journals. Furthermore, the fact of havingchanged the title, the order of the authors, and included a third author in the firstwork that was published, you cannot hide the identical content of both articles.This editorial note is incorporated into the electronic version of the article and will be published in thenext print issue ofSpanish magazine of scientific documentation, v. 34, no. 1, of2011.Madrid, January 26, 2011.