@article{MZ_1977__157_172611,
     author = {J\"urgen Schmidt and Constantine Tsinakis},
     title = {Relative {Pseudo-Complements,} {Join-Extensions,} and {Meet-Retractions.}},
     journal = {Mathematische Zeitschrift},
     pages = {271--284},
     publisher = {mathdoc},
     volume = {157},
     year = {1977},
     zbl = {0351.06010},
     url = {http://geodesic.mathdoc.fr/item/MZ_1977__157_172611/}
}