mysterious metadata links

[lb42]

All but four texts provide a reference using a textgrid identifier <ref target="textgrid:xxx"/> which can easily be translated to an actionable URL. The four which don't are DEU025, 26,34, and 69. They provide a reference like this <ref target="urn:nbn:de:kobv:b4-200905197133"/>
Are these texts not included in TextGrid? if they are, it would be easier to use the textgrid identifier. If not, how should this form of identifier be translated to an actionable URL?