ECO chess codes E4 (idea)

E40 - Nimzo-Indian Defence/Rubstein Variation 
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3

E41 - Nimzo-Indian Defence/Rubinstein Variation/Hubner System
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 c5

E42 - Nimzo-Indian Defence/Rubinstein Variation/ Rubinstein System
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 c5   
5. Ne2

E43 - Nimzo-Indian Defence/Rubinstein Variation/Fischer System
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 b6

E44
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 b6   
5. Ne2

E45
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 b6   
5. Ne2 Ba6

E46 - Nimzo-Indian Defence/Rubinstein Variation
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 O-O

E47
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 O-O   
5. Bd3

E48
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 O-O   
5. Bd3 d5

E49 - Nimzo-Indian Defence/Rubinstein Variation /Closed Saemisch
1. d4 Nf6   
2. c4 e6   
3. Nc3 Bb4   
4. e3 O-O   
5. Bd3 d5   
6. a3 Bc3
7. bc3