"Småvers 18 (I rummets store uendelige)" [Danish title] is number 2357 in the Hans Christian Andersen Center's register of Andersen's literary works, i.e. no. 857 in the category poems (the range 1501 - 2900). BFN 1107.
"Småvers 18 (I rummets store uendelige)" [Danish title] was first published 1879. Further information: Digterens danske Værker 1822-1875 number 1107.
The work was published as a part of Samlede Skrifter af H. C. Andersen. - Tre og Tredivte Bind [Danish title]. (Number 1035. BFN 1079. Category/genre: Collected and miscellaneous writings).
In modern Danish on p. 631 in Johan de Mylius (editor): H.C. Andersen. Samlede digte ('Collected poems', Copenhagen, 2000).