Amend literature

tex/3_mod/3_grid.tex

@@ -9,9 +9,11 @@ Figure \ref{f:grid} shows how the orders' delivery locations are each
     covering the entire service area within a city.
 This gridification step is also applied to the pickup locations separately.
 The lower-left corner is chosen at random.
-\cite{winkenbach2015} apply the same gridification idea and slice an urban
-    area to model a location-routing problem, and \cite{singleton2017} portray
-    it as a standard method in the field of urban analytics.
+Applications of this gridification idea to model location-routing problems
+    can be viewed, for example, in \cite{winkenbach2015}, \cite{bergmann2020},
+    \cite{janjevic2019}, \cite{snoeck2020}, and \cite{janjevic2020}
+    while \cite{singleton2017} portray it as a standard method in the field of
+    urban analytics.
 With increasing pixel sizes, the time series exhibit more order aggregation
     with a possibly stronger demand pattern.
 On the other hand, the larger the pixels, the less valuable become the

tex/references.bib

@@ -56,6 +56,17 @@ pages={8--15},
 publisher={Elsevier}
 }
 
+@article{bergmann2020,
+title={Integrating first-mile pickup and last-mile delivery
+       on shared vehicle routes for efficient urban e-commerce distribution},
+author={Bergmann, Felix M and Wagner, Stephan M and Winkenbach, Matthias},
+year={2020},
+journal={Transportation Research Part B: Methodological},
+volume={131},
+pages={26--62},
+publisher={Elsevier}
+}
+
 @article{box1962,
 title={Some statistical Aspects of adaptive Optimization and Control},
 author={Box, George and Jenkins, Gwilym},
@@ -376,6 +387,26 @@ pages={211--225},
 publisher={INFORMS}
 }
 
+@article{janjevic2019,
+title={Integrating collection-and-delivery points
+       in the strategic design of urban last-mile e-commerce distribution networks},
+author={Janjevic, Milena and Winkenbach, Matthias and Merch{\'a}n, Daniel},
+year={2019},
+journal={Transportation Research Part E: Logistics and Transportation Review},
+volume={131},
+pages={37--67},
+publisher={Elsevier}
+}
+
+@article{janjevic2020,
+title={Designing Multi-tier, Multi-service-level, and Multi-modal
+       Last-Mile Distribution Networks for Omni-Channel Operations},
+author={Janjevic, Milena and Merchan, Daniel and Winkenbach, Matthias},
+year={2020},
+journal={European Journal of Operational Research},
+publisher={Elsevier}
+}
+
 @article{kim2016,
 title={A new Metric of Absolute Percentage Error for Intermittent Demand
        Forecasts},
@@ -559,6 +590,17 @@ number={3},
 pages={199--222}
 }
 
+@article{snoeck2020,
+title={The value of physical distribution flexibility
+       in serving dense and uncertain urban markets},
+author={Snoeck, Andr{\'e} and Winkenbach, Matthias},
+year={2020},
+journal={Transportation Research Part A: Policy and Practice},
+volume={136},
+pages={151--177},
+publisher={Elsevier}
+}
+
 @article{stitson1999,
 title={Support Vector Regression with ANOVA Decomposition Kernels},
 author={Stitson, Mark and Gammerman, Alex and Vapnik, Vladimir