The link for Sandoll Gothic is here: https://www.sandoll.co.kr/SandollWeb/shop/product_down_read.asp?idx=187&listType=2

However, purchasing the font is extremely convoluted for a non-Korean, mainly because the site is only available in Korean. You have to become a member, which requires you to e-mail or fax them a copy of your passport or driver’s licence unless you’re Korean and have a national identification number. Unless you have a working knowledge of Korean, you’ll need a Korean speaker to guide you through the steps. The situation will be similar with other Korean foundries. You have South Korea’s excessive regulation of internet commerce to thank...

There is a vendor I found whose page is in English offering mostly Yoon Design fonts: http://asiasoft.com/bin/category/?mainCatID=2&subCatID=9

Alternatively, if you have $1585 to spare, the Korean version of Adobe InDesign CS2 comes bundled with an impressive range of releases by all the major Korean foundries...

Slightly off-topic:
There’s an exhibition about ‘Ahn Sang Soo. The Beauty of Hangul’ at Klingspor Museum in Offenbach, Germany. More information.