  Bibliometric information retrieval in databases can employ different
strategies. Com-monly, queries are performed by searching in title, abstract
and/or author keywords (author vocabulary). More advanced queries employ
database keywords to search in a controlled vo-cabulary. Queries based on
search terms can be augmented with their citing papers if a re-search field
cannot be curtailed by the search query alone. Here, we present another
strategy to discover the most important papers of a research field. A marker
paper is used to reveal the most important works for the relevant community.
All papers co-cited with the marker paper are analyzed using reference
publication year spectroscopy (RPYS). For demonstration of the marker paper
approach, density functional theory (DFT) is used as a research field.
Compari-sons between a prior RPYS on a publication set compiled using a
keyword-based search in a controlled vocabulary and three different co-citation
RPYS (RPYS-CO) analyses show very similar results. Similarities and differences
are discussed.
