no. 3
A universal construction for projective Hjelmslev planes of level n
Compositio Mathematica, Tome 71 (1989) no. 3, pp. 285-294. 
@article{CM_1989__71_3_285_0,
     author = {Hanssens, G. and Van Maldeghem, H.},
     title = {A universal construction for projective {Hjelmslev} planes of level $n$},
     journal = {Compositio Mathematica},
     pages = {285--294},
     publisher = {Kluwer Academic Publishers},
     volume = {71},
     number = {3},
     year = {1989},
     mrnumber = {1022046},
     zbl = {0709.51010},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1989__71_3_285_0/}
}
TY  - JOUR
AU  - Hanssens, G.
AU  - Van Maldeghem, H.
TI  - A universal construction for projective Hjelmslev planes of level $n$
JO  - Compositio Mathematica
PY  - 1989
SP  - 285
EP  - 294
VL  - 71
IS  - 3
PB  - Kluwer Academic Publishers
UR  - http://archive.numdam.org/item/CM_1989__71_3_285_0/
LA  - en
ID  - CM_1989__71_3_285_0
ER  - 
%0 Journal Article
%A Hanssens, G.
%A Van Maldeghem, H.
%T A universal construction for projective Hjelmslev planes of level $n$
%J Compositio Mathematica
%D 1989
%P 285-294
%V 71
%N 3
%I Kluwer Academic Publishers
%U http://archive.numdam.org/item/CM_1989__71_3_285_0/
%G en
%F CM_1989__71_3_285_0
Hanssens, G.; Van Maldeghem, H. A universal construction for projective Hjelmslev planes of level $n$. Compositio Mathematica, Tome 71 (1989) no. 3, pp. 285-294. http://archive.numdam.org/item/CM_1989__71_3_285_0/

1 B. Artmann: Existenz und projektive Limiten von Hjelmslev-Ebenen n-ter Stufe, Atti del Convegno di Geometria Combinatoria e sue Applicazioni, Perugia (1971), 27-41. | MR | Zbl

2 D.A. Drake: Construction of Hjelmslev planes, J. Geom. 10 (1977) 179-193. | MR | Zbl

3 G. Hanssens and H. Van Maldeghem: On projective Hjelmslev planes of level n, to appear. | MR | Zbl

4 M.A. Ronan: A free construction of buildings with no rank 3 residue of spherical type, in "Buildings and the geometry of diagrams", Lect. Notes 1181, Springer-Verlag (1986) pp. 242-248. | MR | Zbl

5 H. Van Maldeghem: Non-classical triangle buildings, Geom. Ded. 24 (1987) 123-206. | MR | Zbl