diff --git a/chapter01.tex b/chapter01.tex
index 2abce8b..859acf9 100644
--- a/chapter01.tex
+++ b/chapter01.tex
@@ -928,7 +928,7 @@ Google Code Jam and Yandex.Algorithm.
 Of course, companies also use those contests for recruiting:
 performing well in a contest is a good way to prove one's skills.
 
-\section{Books}
+\section{Resources}
 
 \subsubsection{Competitive programming books}
 
@@ -937,12 +937,11 @@ concentrate on competitive programming and algorithmic problem solving:
 
 \begin{itemize}
 \item S. Halim and F. Halim:
-\emph{Competitive Programming 3: The New Lower Bound of Programming Contests}, 2013
+\emph{Competitive Programming 3: The New Lower Bound of Programming Contests} \cite{hal13}
 \item S. S. Skiena and M. A. Revilla:
-\emph{Programming Challenges: The Programming Contest Training Manual},
-Springer, 2003
-\item \emph{Looking for a Challenge? The Ultimate Problem Set from
-the University of Warsaw Programming Competitions}, 2012
+\emph{Programming Challenges: The Programming Contest Training Manual} \cite{ski03}
+\item K. Diks et al.: \emph{Looking for a Challenge? The Ultimate Problem Set from
+the University of Warsaw Programming Competitions} \cite{dik12}
 \end{itemize}
 
 The first two books are intended for beginners,
@@ -956,9 +955,9 @@ Some good books are:
 
 \begin{itemize}
 \item T. H. Cormen, C. E. Leiserson, R. L. Rivest and C. Stein:
-\emph{Introduction to Algorithms}, MIT Press, 2009 (3rd edition)
+\emph{Introduction to Algorithms} \cite{cor09}
 \item J. Kleinberg and É. Tardos:
-\emph{Algorithm Design}, Pearson, 2005
+\emph{Algorithm Design} \cite{kle05}
 \item S. S. Skiena:
-\emph{The Algorithm Design Manual}, Springer, 2008 (2nd edition)
+\emph{The Algorithm Design Manual} \cite{ski08}
 \end{itemize}
diff --git a/chapter06.tex b/chapter06.tex
index 489ab4e..8b909af 100644
--- a/chapter06.tex
+++ b/chapter06.tex
@@ -103,8 +103,12 @@ is 6, the greedy algorithm produces the solution
 $4+1+1$ while the optimal solution is $3+3$.
 
 It is not known if the general coin problem
-can be solved using any greedy algorithm.
+can be solved using any greedy algorithm\footnote{However, it is possible
+to \emph{check} in polynomial time
+if the greedy algorithm presented in this chapter works for
+a given set of coins \cite{pea05}.}.
 However, as we will see in Chapter 7,
+in some cases,
 the general problem can be efficiently
 solved using a dynamic
 programming algorithm that always gives the
diff --git a/chapter13.tex b/chapter13.tex
index 12938d0..f6461be 100644
--- a/chapter13.tex
+++ b/chapter13.tex
@@ -24,7 +24,9 @@ for finding shortest paths.
 
 \index{Bellman–Ford algorithm}
 
-The \key{Bellman–Ford algorithm} \cite{bel58} finds the
+The \key{Bellman–Ford algorithm}\footnote{The algorithm is named after
+R. E. Bellman and L. R. Ford who published it independently
+in 1958 and 1956, respectively \cite{bel58,for56a}.} finds the
 shortest paths from a starting node to all
 other nodes in the graph.
 The algorithm can process all kinds of graphs,
@@ -331,7 +333,9 @@ original Bellman–Ford algorithm.
 
 \index{Dijkstra's algorithm}
 
-\key{Dijkstra's algorithm} \cite{dij59} finds the shortest
+\key{Dijkstra's algorithm}\footnote{E. W. Dijkstra published the algorithm in 1959 \cite{dij59};
+however, his original paper does not mention how to implement the algorithm efficiently.}
+finds the shortest
 paths from the starting node to all other nodes,
 like the Bellman–Ford algorithm.
 The benefit in Dijsktra's algorithm is that
@@ -594,7 +598,9 @@ at most one distance to the priority queue.
 
 \index{Floyd–Warshall algorithm}
 
-The \key{Floyd–Warshall algorithm} \cite{flo62}
+The \key{Floyd–Warshall algorithm}\footnote{The algorithm
+is named after R. W. Floyd and S. Warshall
+who published it independently in 1962 \cite{flo62,war62}.}
 is an alternative way to approach the problem
 of finding shortest paths.
 Unlike the other algorihms in this chapter,
diff --git a/list.tex b/list.tex
index 9cf1518..8939e38 100644
--- a/list.tex
+++ b/list.tex
@@ -38,12 +38,12 @@
 \bibitem{ben86}
   J. Bentley.
   \emph{Programming Pearls}.
-  Addison-Wesley, 1986.
+  Addison-Wesley, 1999 (2nd edition).
 
 \bibitem{bou01}
   C. L. Bouton.
   Nim, a game with a complete mathematical theory.
-  \emph{Annals of Mathematics}, 3(1/4):35--39, 1901.
+pro  \emph{Annals of Mathematics}, 3(1/4):35--39, 1901.
 
 % \bibitem{bur97}
 %   W. Burnside.
@@ -54,11 +54,20 @@
   Codeforces: On ''Mo's algorithm'',
   \url{http://codeforces.com/blog/entry/20032}
 
+\bibitem{cor09}
+  T. H. Cormen, C. E. Leiserson, R. L. Rivest and C. Stein.
+  \emph{Introduction to Algorithms}, MIT Press, 2009 (3rd edition).
+
 \bibitem{dij59}
   E. W. Dijkstra.
   A note on two problems in connexion with graphs.
   \emph{Numerische Mathematik}, 1(1):269--271, 1959.
 
+\bibitem{dik12}
+  K. Diks et al.
+  \emph{Looking for a Challenge? The Ultimate Problem Set from
+  the University of Warsaw Programming Competitions}, University of Warsaw, 2012.
+
 % \bibitem{dil50}
 %   R. P. Dilworth.
 %   A decomposition theorem for partially ordered sets.
@@ -104,6 +113,11 @@
   Algorithm 97: shortest path.
   \emph{Communications of the ACM}, 5(6):345, 1962.
 
+\bibitem{for56a}
+  L. R. Ford.
+  Network flow theory.
+  RAND Corporation, Santa Monica, California, 1956.
+
 \bibitem{for56}
   L. R. Ford and D. R. Fulkerson.
   Maximal flow through a network.
@@ -152,7 +166,9 @@
 %   On representatives of subsets.
 %   \emph{Journal London Mathematical Society} 10(1):26--30, 1935.
 
-  On representatives of subsets. J. London Math. Soc, 10(1), 26-30.
+\bibitem{hal13}
+  S. Halim and F. Halim.
+  \emph{Competitive Programming 3: The New Lower Bound of Programming Contests}, 2013.
 
 \bibitem{hel62}
   M. Held and R. M. Karp.
@@ -198,6 +214,10 @@
   Efficient randomized pattern-matching algorithms.
   \emph{IBM Journal of Research and Development}, 31(2):249--260, 1987.
 
+\bibitem{kle05}
+  J. Kleinberg and É. Tardos.
+  \emph{Algorithm Design}, Pearson, 2005.
+
 % \bibitem{kas61}
 %   P. W. Kasteleyn.  
 %   The statistics of dimers on a lattice: I. The number of dimer arrangements on a quadratic lattice.
@@ -247,6 +267,11 @@
 %   \emph{Sitzungsberichte des deutschen naturwissenschaftlich-medicinischen Vereines
 %   für Böhmen "Lotos" in Prag. (Neue Folge)}, 19:311--319, 1899.
 
+\bibitem{pea05}
+  D. Pearson.
+  A polynomial-time algorithm for the change-making problem.
+  \emph{Operations Research Letters}, 33(3):231--234, 2005.
+
 \bibitem{pri57}
   R. C. Prim.
   Shortest connection networks and some generalizations.
@@ -271,6 +296,15 @@
   A strong-connectivity algorithm and its applications in data flow analysis.
   \emph{Computers \& Mathematics with Applications}, 7(1):67--72, 1981.
 
+\bibitem{ski08}
+  S. S. Skiena.
+  \emph{The Algorithm Design Manual}, Springer, 2008 (2nd edition).
+
+\bibitem{ski03}
+  S. S. Skiena and M. A. Revilla.
+  \emph{Programming Challenges: The Programming Contest Training Manual},
+  Springer, 2003.
+
 \bibitem{spr35}
   R. Sprague.
   Über mathematische Kampfspiele.
@@ -306,6 +340,11 @@
   \emph{Des Rösselsprunges einfachste und allgemeinste Lösung}.
   Schmalkalden, 1823.
 
+\bibitem{war62}
+  S. Warshall.
+  A theorem on boolean matrices.
+  \emph{Journal of the ACM}, 9(1):11--12, 1962.
+
 % \bibitem{zec72}
 %   E. Zeckendorf.
 %   Représentation des nombres naturels par une somme de nombres de Fibonacci ou de nombres de Lucas.