E.g. on the front page of the manual it says:
The PhD-thesis "Regularity Aspects for Combinatorial Simplicial Surfaces" of Markus Baumeister
The book "Simplicial Surfaces of Congruent Triangles" by Alice C. Niemeyer, Wilhelm Plesken, Daniel Robertz, and Ansgar W. Strzelczyk (unpublished)
Both of these could be entries in your .bib file, but the thesis could then even include a DOI & link to it online.
And perhaps some of your papers using this package could be listed as well somewhere in the manual (and referenced in the bib). This would help anyone interested in what your package is capable of -- they can look at the papers and thesis to get a better idea
E.g. on the front page of the manual it says:
Both of these could be entries in your .bib file, but the thesis could then even include a DOI & link to it online.
And perhaps some of your papers using this package could be listed as well somewhere in the manual (and referenced in the bib). This would help anyone interested in what your package is capable of -- they can look at the papers and thesis to get a better idea