What's wiser - since an applicant has the duty to disclose prior art to a point would it be better to send it anonymously to the owner or jump through all the hoops it takes to get it to an examiner? In question is a child application. The prior art is clear and concise from a book of software that's 2 years older than the original patent priority date.
1) Third party submission/observation allows for detailed remarks
As DonQuiKong notes in an OP comment, a third party submission (US) or third party observation (outside US) allows accompanying statements on the relevance of specific portions of the prior art presented. However, it is important to note that "arguments" relating to patentability are not allowed (at least in the US), and would likely result in the TPS being ignored (and there may not be a second chance to send due to the 6 month window). Therefore, statements should take the form of "this prior art discloses X [which is claimed in the patent application]", but not "the patent claim is invalid due to obviousness over this prior art". Claim charts specifying the exact mapping between prior art content and the contested claims are preferable, as they "spoon feed" the examiner and minimize the amount of effort required to incorporate the third party submission into an Office Action.
On the other hand, a US applicant's duty of disclosure only requires an IDS (information disclosure statement) listing the bibliographic information of the prior art (e.g. patent number, article title), but does not require disclosure of specific portions or relevance thereof. Therefore, as quite often does happen, an examiner may ignore the applicant-submitted IDS, thus adding the prior art to the pile of prior art the patent is presumed to be valid over (which is bad). However, one potential benefit of serving the applicant is that if the art is material, and the applicant doesn't follow through with submitting the art to the examiner, you may have an argument for patent unenforceability later (due to "inequitable conduct").
2) Domestic patent prior art is preferable
Domestic patent prior art (or at least prior art in the language of the examiner) will likely be given the fullest consideration. It's what the examiner is used to, and there will be no issues proving the publication date. Therefore, even if you found great non-patent prior art, I would still endeavor to find a patent publication analogue.
Further patent applications are written to contemplate wide-ranging applications of the ideas, and often will be more relevant than "narrow" non-patent prior art, which may even disparage or teach against certain embodiments.
3) You may not even want to send the prior art
Consider carefully how the outcome of sending the prior art affects you. If you have no commercial stakes in the outcome, and this is simply an interesting learning experience, then feel free to go ahead. However, with such limited grounds for argument in front of the examiner (esp. if sending the prior art through the applicant in an IDS), you are putting your fate in the examiner's hands. Also, you note that you are dealing with a child/continuation application. This would seem to imply that a parent application has already been allowed, and therefore there will likely be problem claims anyway, which this prior art can't really help with beyond placing a presumption of invalidity on the former claims via after-the-fact examiner arguments (assuming the child claims are similar enough to invite such arguments).
Submitting art to an examiner or applicant reduces uncertainty of the valid patent scope. Therefore, it's a double-edged sword: good if the uncertainty is reduced in your favor (e.g. pending claims rejected over submitted art) and vice versa (i.e. bad if examiner ignores art or disagrees with its relevance).
Some examiners are very diligent in finding prior art and would take advantage of what's provided. But more likely than not, your art will end up with an examiner who wants to put forth the minimum effort to get the job done, and does not have stakes in the outcome. Note that it's not uncommon for examiner's to just largely ignore third party submissions. Therefore, you may "waste" your prior art bullet, and have a higher hurdle to overcome if trying to present the same arguments in the future (or perhaps be prevented from bringing the same arguments altogether). In any case, review the prosecution history (and examiner statistics) to get a better idea of the examiner at hand.
There are both pros and cons to sending "strong" and "weak" prior art. "Strong" prior art may make a rejection clear to an examiner, but if the examiner fails to utilize it, you're in a much worse position than if you didn't send anything. On the other hand, "weak" prior art will require the examiner to do more work to understand what's going on (which the examiner may just give up on and ignore), but it also provides an opportunity to "test the waters" and perhaps set the examiner on a new prior art search path without giving away your crown jewel (if you have one).
Further, sending prior art alerts the applicant that someone out their cares and may even be afraid of the patent. This may encourage the applicant to work more vigorously to obtain claims (more prosecution rounds, more applications), and works against your goal of not having such claims to deal with. Also, it lets the applicant know that someone else thinks the claims are valuable, which could affect licensing negotiations or probability of infringement suit in the future (esp. if the applicant knows who sent the prior art).
Finally, submitting the prior art now gives the applicant a great opportunity to appropriately amend the claims and create a stronger patent. On the other hand, if you hold onto (esp. "strong") prior art, you may easily destroy the patent in future litigation, where the applicant has less (or no) recourse to amend claims.