add paper links

Author: egisatoshi

README.md

@@ -6,17 +6,28 @@ This is the repository of the interpreter of Egison.
 
 For more information, visit <a target="_blank" href="https://www.egison.org">our website</a>.
 
-## Non-Linear Pattern-Matching for Non-Free Data Types
+## Refreed Papers
 
-We can describe non-linear pattern-matching for non-free data types in Egison.
+### Pattern Matching
+
+* Satoshi Egi, Yuichi Nishiwaki: [Non-linear Pattern Matching with Backtracking for Non-free Data Types](https://arxiv.org/abs/1808.10603) (APLAS 2018)
+* Satoshi Egi: [Loop Patterns: Extension of Kleene Star Operator for More Expressive Pattern Matching against Arbitrary Data Structures](https://arxiv.org/abs/1809.03252) (Scheme Workshop 2018)
+
+## Tensor Index Notation
+
+* Satoshi Egi: [Scalar and Tensor Parameters for Importing Tensor Index Notation including Einstein Summation Notation](https://arxiv.org/abs/1702.06343) (Scheme Workshop 2017)
+
+## Non-Linear Pattern Matching for Non-Free Data Types
+
+We can describe non-linear pattern matching for non-free data types in Egison.
 A non-free data type is a data type whose data have no canonical form, a standard way to represent that object.
 For example, multisets are non-free data types because the multiset {a,b,b} has two other equivalent but literally different forms {b,a,b} and {b,b,a}.
-Expressive pattern-matching for these data types enables us to write elegant programs.
+Expressive pattern matching for these data types enables us to write elegant programs.
 
 ### Twin Primes
 
-We can use pattern-matching for enumeration.
-The following code enumerates all twin primes from the infinite list of prime numbers with pattern-matching!
+We can use pattern matching for enumeration.
+The following code enumerates all twin primes from the infinite list of prime numbers with pattern matching!
 
 <hr/>
 <img width="100%" src="https://raw.githubusercontent.com/egison/egison/master/images/twin-primes.png" />
@@ -50,8 +61,8 @@ We can write program to solve the travelling salesman problem in a single patter
 <hr/>
 
 Aren't these exciting?
-The pattern-matching of Egison is very powerful.
-We can use it for pattern-matching also against graphs and tree-structures such as XML.
+The pattern-matching facility of Egison is very powerful.
+We can use it for pattern matching also for graphs and tree-structures such as XML.
 
 ## Egison as a Computer Algebra System
 
@@ -278,7 +289,7 @@ Here are more samples.
 
 ## Comparison with Related Work
 
-There are <a target="_blank" href="https://ghc.haskell.org/trac/ghc/wiki/ViewPatterns#Relatedwork">a lot of existing work</a> for pattern-matching.
+There are <a target="_blank" href="https://ghc.haskell.org/trac/ghc/wiki/ViewPatterns#Relatedwork">a lot of existing work</a> for pattern matching.
 
 The advantage of Egison is that it fulfillss **all the following two requirement** at the same time.
 
@@ -290,7 +301,7 @@ Additionally, it fulfills the following requirements.
 (3) Polymorphism of patterns.
 (4) Pattern matching with infinitely many results.
 
-Please read <a target="_blank" https://arxiv.org/abs/1808.10603">our paper</a> for details.
+Please read <a target="_blank" href="https://arxiv.org/abs/1808.10603">our paper</a> for details.
 
 ## Installation
 
@@ -336,8 +347,8 @@ If we type a 'Tab' key after a closed parenthesis, the next closed parenthesis w
 List of sections in the tutorial.
 1: Calculate numbers
 2: Basics of functional programming
-3: Basics of pattern-matching
-4: Pattern-matching against various data types
+3: Basics of pattern matching
+4: Pattern matching against various data types
 5: Symbolic computation
 6: Differential geometry: tensor analysis
 7: Differential geometry: differential forms