Let me help you out a little: for your first lengthy quotation from the Washington Post, I was able to find THIS reputable source, CalTech, as a reference. It's helpful to include a link to the source material whenever you post a quote or reference. In that way, readers can review the source material in context. I found the article in the Washington Post archives, too, but they wanted money to view the entire article, and I probably would've ran afoul of the copyright laws had I reprinted it here.

There is a specific rebuttal to that Washington Post article HERE, in which the author, Phil Plait, actually contacted the two astronomers, Neugebauer and Houck, mentioned in the article. He received a reply from Neugebauer, and found that the truth about the "mystery object" was not as described in the Washington Post article. Please take the time to read Plait's article, and the reference links it contains, to verify that the IRAS object(s) were not then, and are not now, Planet X.

For your second quote, I was able to find a link to the NY Times article through their archives HERE . But I was also able to find a NY Times article titled "Evidence for Planet X Evaporates in Spotlight of New Research" HERE, published 6/1/1993. From that article, "The apparent death blow to the Planet X theory was published in the May issue of The Astronomical Journal by Dr. E. Myles Standish Jr., an astrophysicist at the Jet Propulsion Laboratory in Pasadena, Calif. His analysis, which includes significant corrections of the expected orbits of Uranus and Neptune, is the first to make use of an extremely accurate measurement of Neptune's mass made by Voyager 2 in 1989. His recalculation of the motions and masses of the outer planets shows that they are moving just as one would expect if there were no planet beyond them exerting a gravitational tug on their orbits. Despite the longstanding reluctance of a few theorists to abandon the Planet X hypothesis, Dr. Standish concludes, "There remains no need to hypothesize the existence of a 10th planet in the solar system."

I wasn't able to find the source of your third quotation, but it doesn't matter, because the flyby of Voyager 2 of Neptune in 1989 negates all previous calculations, because of the corrected and much more accurate mass for Neptune, as described in the previous NY Times article of 6/1/1993.

So, unless you've got more game than some 27 year old references, which have since been rendered obsolete by additional scientific exploration and observation, there still is no valid claim for Planet X/Nibiru. I ask again, and will keep asking, if it exists, where is it? What are it's current coordinates? What are it's orbital elements, so that we can know where it's going to be?